Restoration / Repair of Tektronix 545 - Finished. - Page 1
Forum section: electronics / repair

author: VK5RC
author_rank: Unknown
timestamp: September 04, 2016, 12:26:00 pm
content: I found a Tek 545 for sale on eBay that was quite close to me (the postage on 30kg is not cheap) and the price was pretty good. No major bits missing no major trauma.I have posted a bit of my work to date on Martin.M s excellent Tektronix repair thread but thought I should give this beast its own thread.I appreciate the guidance I have received from Martin.M and other EEV bloggers.The front picture looks really good but open the side covers and find 2016-1957 years of dust . a little bit of surface rusting but nothing serious.

author: VK5RC
author_rank: Unknown
timestamp: September 04, 2016, 12:39:16 pm
content: A rough plan to tackleVacuum out the bit bits and most of the free dustStart at the top of one side (RHS) cleaning with mainly IsoPropyl Alcohol swabs / cotton buds (Q tips)Cleaning tube tops with distilled water, bases with IPARusty bolts (only a few) remove, brass brush then a very light smear of Gun Oil (Braek Free LP) for rust preventionAluminium chassis - IPA clean with cotton rag then also a very light rub with Gun OilTest tubes ; using uTracer from dosforever - a great kit ,http://www.dos4ever.com/uTracer3/uTracer3_pag0.htmlTest major filtering capacitorsClean / remount fan - rubber suspension had perishedClean / test plug In.Final voltage rail testingSwitch onFault tracingFront panel tidy upChassis repair / resprayEdit; I keep thinking of things I will need to do!!!

author: VK5RC
author_rank: Unknown
timestamp: September 04, 2016, 12:44:17 pm
content: The RHS of the Tek 545 has inside the chassis a pivoted subframe or 'door' that swings out giving pretty good access to the large number of tubes. Lodged near the base of a tube I found a piece of wire, not sure if it had done any mischief.The tubes are found not only on the base of the chassis facing up, the 'door' facing in but also the roof facing down!Below is a photo of the RHS after a fair bit of cleaning.

author: VK5RC
author_rank: Unknown
timestamp: September 04, 2016, 12:49:37 pm
content: After a lot of cleaning, needed a bit of a break so I tackled the fan. I was sup prised to be able to find a very close fit from my local RS components supply house.Fan powers up with 110v AC, some silicon oil (thanks Martin.M) ordered .

author: VK5RC
author_rank: Unknown
timestamp: September 04, 2016, 01:04:31 pm
content: The tube testing has been a bit of a learning curve for me as I haven't used tubes in seriousness.The uTracer is basically 3 computer controlled switch mode power supplies 1 for the heater and can supply an Amp or two and two high voltage SMPSU. These can supply 350v DC for the few milliseconds each test is carried out. This allows a lot lower power input, lower thermal stress on the tube under test and as the high voltage isn't around for long the opportunity to electrocute yourself also goes down! The uTracer can measure the current supplied as well as the voltage and graph / trace the resultsYou have to find the various types of tube sockets needed and wiring them is a challenge (see photo below), fortunately the pin numbering system of tubes NEVER changed.A peg board is required to link the heater to the correct pin number, I followed the uTracer kits suggestion of colour coding the wire but also making a little card to reduce pegboard errors.Finding the data sheets wasn't too bad.A photo below shows a tube test and my paper log of the valves tested and the result.One of the power twin triode voltage regulators (6080) has a dud side and I think one of the smaller signal type twin triode 6BQ7 had been replaced by a 6DJ8 I think (the number has come off but the gain was way too big)

author: matthieu.e
author_rank: Regular Contributor
timestamp: September 04, 2016, 02:06:13 pm
content: Hi,That is a very nice scope with all the tubes !Your restauration seems to be in the good way.All the functions of your scope are OK ?I have an analog scope, a little Hameg HM 307 in addition to my digital DSOX20002A. I don't know why but I am attached to the HM307 and want to keep it.I see you have a U tracer ? What is your opinion on it ?I plan to buy the U tracer or to make one myself using variable power supply and Matlab script. I would like to match tubes when I work on audio amplifier.Could you present us your work bench ?

author: VK5RC
author_rank: Unknown
timestamp: September 05, 2016, 12:02:54 am
content: Hi matthieu.eMy semi -recent work bench photos are in the posthttps://www.eevblog.com/forum/chat/whats-your-work-benchlab-look-like-post-some-pictures-of-your-lab/2109/reply no 2109While the uTracer is not cheap, it isverywell made, includes firmware in the PIC, a professionally made PCB, I think its designer is an EE. The PC based software works well with a USB to serial interface (note one type of USB/Serial chipset is preferred). If I blew it up today I would get another for sure.I certainly would not be able to make something of similar quality esp for the price. The manual is good as well. You have to allow some extra money for a box but also the tube bases are not cheap, I went for as many as I could find on the assumption that after I made it , I would be very reluctant to add more. I think it works well, a lot better than most "tube testers".I am not an EE but an enthusiastic Amateur radio op, and have done a bit of restoration, partly as I like some of the older gear but also as a learning exercise. i have repaired / restored an HP 5245L, a Tek 453, , HP 5342, and a few others.I note you like your Hameg gear, some of the older gear has a better user interface, for example my HP 3314 is my go to frequency generator as it is so intuitive to use and I often don't really need the higher precision of the newer gear.The Tek 545 is still in the repair phase so I haven't switched it on yet as that could be a bad experience. As I work, have family etc it may be some weeks before I get to that stage.regards Rob

author: FlyingHacker
author_rank: Frequent Contributor
timestamp: September 05, 2016, 02:40:54 am
content: Looks like fun. I recently did a 564.I replaced all my electrolytics with modern caps. If you do that don't make my mistake of forgetting to ground the negative pins to the chassis where appropriate (when the original was case grounded).All my pots needed electro solve AND CRC-26 to get smooth.Dunno about the 545, but my 564 has some HV (-3000V) outside the HV can. I got too close to that and took a nasty hit on my hand... Keep on hand in your pocket

author: VK5RC
author_rank: Unknown
timestamp: September 05, 2016, 11:53:31 am
content: @FlyingHackerThanks for the comments, I am seriously chicken when it comes to anything over 100V. I recall the 545 is in that HV range.I have tested quite a few of the can type capacitors on the RHS and all had ESR <0.2 Ohms, Martin.M comments in his Tek repair post the Tek Caps are pretty reliableAt this stage I will go with those caps at switch on. Will check for ripple etc.My unit is dirty / dusty and I think has old cigarette smoke residue for good measure but otherwise not too bad, all the pots and switches mechanically turn nicely. Electrically who knows, but I figure a good clean and test of tubes and caps before has to help the electrical odds in my favour .

author: richnormand
author_rank: Unknown
timestamp: September 07, 2016, 03:23:22 am
content: Nice resto job on a worthwhile instrument.I got a Tek 545A with about 10 plug-ins (including the fast risetime one with the mercury relay for calibration and adjusting the delay line) about 40 years ago, surplussed when A.V. Roe (Avro Arrow) got creamed. Fully restored then. Loved the ceramic rails with silver solder and the fact they included spare solder for future repairs inside the unit. Also came with full manuals.It still works today and in used occasionally when doing high voltage or risky stuff for semiconductors scopes. Great to warm up the basement in winter with it's nearly 50 tubes. These front-end tubes can take a beating and still go!Let me know if you need inside photos, tube pinouts or specs or measurements to help the process.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: September 07, 2016, 09:21:30 am
content: Quote from: richnormand on September 07, 2016, 03:23:22 amGreat scope, but what plugin is that? Type N?

author: VK5RC
author_rank: Unknown
timestamp: September 07, 2016, 12:25:53 pm
content: @richnormand lovely photo, mine is the plain 545 so the screen only has 4 vertical divisions, I really appreciate the offer of support, I will try not to bother.Work and family commitments may slow me down.Regards Rob

author: richnormand
author_rank: Unknown
timestamp: September 07, 2016, 03:28:02 pm
content: Quote from: VK5RC on September 07, 2016, 12:25:53 pmActually it has only 4 vertical divisions. I replaced the graticule plexi with this one to get red backlight and a more uniform light when I was using the camera. I still have the original one though.

author: richnormand
author_rank: Unknown
timestamp: September 07, 2016, 03:34:07 pm
content: Quote from: Alex Eisenhut on September 07, 2016, 09:21:30 amIt's a Type 53/54C

author: Martin.M
author_rank: Frequent Contributor
timestamp: September 07, 2016, 04:39:19 pm
content: 53/54C is the early version of the CA,most of application of them both is identical.They are good for up to 30mc, inside are 15 tubes workingThe typical probes are a pair of P6006Early plugins (and scopes) use oftenly the UHF plug, PL259 instead of the BNC. The P6006 Probes also. It is a good idea to have some adaptors PL to BNC in the houseRich you have also the little 305DMM there, very nice to see a living oneI am interested to a picture from that scope mobil "lab cart" never seen that.The typical scope mobil of 545A and relatives is the Type 202-2 (with a housing for 2 plugins to swap)greetingsMartin

author: richnormand
author_rank: Unknown
timestamp: September 07, 2016, 05:14:49 pm
content: Quote from: Martin.M on September 07, 2016, 04:39:19 pmThe 305 gets a fresh set of NiCad every 5 years or so. Used when I need to float a scope for HV work. A few months ago I used it to adjust the PWM tracking extractor voltage for a CW x-ray tube. Just have to make sure it is well isolated on about 4 cm of dry plywood and all wires setup and isolated properly before turning on the machine. Nice and dependable portable unit.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: September 07, 2016, 11:40:37 pm
content: Quote from: richnormand on September 07, 2016, 03:34:07 pmYes, but I meant this part :including the fast risetime one with the mercury relay for calibration and adjusting the delay line

author: richnormand
author_rank: Unknown
timestamp: September 08, 2016, 02:12:09 am
content: Quote from: Alex Eisenhut on September 07, 2016, 11:40:37 pmHa! sorry about that.It's type 53/54P Plug-in Test Unit fast rise-time mercury pulser.Here are some pictures.Front panel.Inside panel is at 45 degrees so it will work with the scope upright and on its side.Inside photo shows the schematic diagram and supply.Second inside photo shows the electro-magnet to actuate the mercury reed switch.Once you see the distributed tubes (valves) in parallel for the vertical deflection in the scope and the insane number of adjustable trims in the transmission line between them you will see how this plugin was most useful when you changed several tubes for a good match.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: September 08, 2016, 02:17:50 am
content: Yoicks! I've only seen that called the Type P. I see now. You can get the TU7, it's better, has more thingies on it.

author: VK5RC
author_rank: Unknown
timestamp: September 08, 2016, 11:40:09 am
content: Serious "Plug In Envy" happening here; better get my old girl working first

author: VK5RC
author_rank: Unknown
timestamp: September 10, 2016, 07:32:48 am
content: Working on the top HV supply, found the main filter caps (10uF) for the 150, 350 V rails has an ESR of 15ohms or so, Have ordered some new caps and will prob do the 'hide them in the old can' trick. May explain why one side of one regulator tube (6080) had sold outBelow are the before and after of the LHS, all tubes tested OK. Big fan now of window cleaning liquid first then Isopropyl alcohol. (Thanks Martin.M)

author: Martin.M
author_rank: Frequent Contributor
timestamp: September 10, 2016, 01:00:41 pm
content: looks fineTip: when the part No from a tube begins with 154 its a tube, is there a 157 in begin, it is a selected tube.do not swap tubes by cleaning, they have to go in the socket where they comming from.6080, is mostly OK, oftenly I found tired 6AU6 or a tired 12AT7, 12AX7 in the PSU, the driver stages from the 6080 are hard working parts.greetingsMartin

author: Cyberdragon
author_rank: Super Contributor
timestamp: September 10, 2016, 01:02:51 pm
content: Quote from: VK5RC on September 10, 2016, 07:32:48 amDid you wash the tubes?! That means you washed off the silkscreen on them!EDIT: it looks like some of it survived, just be careful cleaning tubes.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: September 10, 2016, 01:38:49 pm
content: Quote from: Cyberdragon on September 10, 2016, 01:02:51 pmOnly some tubes have water soluble markings, usually it's etched into the glass. Unfortunately, it's the nice looking ornate logos that wash off.

author: FlyingHacker
author_rank: Frequent Contributor
timestamp: September 11, 2016, 12:17:52 am
content: Yeah, I washed a lot off mine by mistake... It took me two or three to notice.Oh well. Not much I can do now.

author: Fireball XL5
author_rank: Newbie
timestamp: September 11, 2016, 01:02:56 am
content: Quote from: Alex Eisenhut on September 10, 2016, 01:38:49 pmIs there a cleaning method to prevent lose of silkscreen or label? If so, could it be added to the Restoration sticky at the top of this section?(Unless it's already there and I missed it)Also, I'm in awe of the folks who take on a project to bring back these devices I took for granted (shame on me). Amazing work!

author: VK5RC
author_rank: Unknown
timestamp: September 11, 2016, 08:01:00 am
content: GE tubes often have a water soluble label but the tube number is etched in.I was aware of this issue and as most of the dirt is on the top of the tubes - that was the area that got most attention, so most of the print (that was left) stayed on.Some of the labels didn't like even handling, but a lot of tubes were not seated well, some corrosion and dirt in the socket.Edit : window cleaner and IPA was only used on the chassis, tubes were cleaned with distilled water for tops, IPA for the pins.@martin.m thanks re the part number clue, all the tubes went back in to their own sockets, except my 1 dud 6080, replaced with a tested NOS.

author: VK5RC
author_rank: Unknown
timestamp: September 11, 2016, 08:32:06 am
content: I tested (traced the output of every tube) rather interestingly the 'matched pairs' of the distributed amp weren't v close, but no changes made.

author: VK5RC
author_rank: Unknown
timestamp: September 16, 2016, 12:10:52 pm
content: The centre frame support was chromed and it was peeling badly, some bits had disappeared into the bowels of the unit, hard to find and remove!Below is a photo of the centre frame removed and the handles taken off, just before it went to the sand blasting (well glass bead actually) cabinet.I went for a Chrome Paint which is looking alright so far.

author: Cubdriver
author_rank: Unknown
timestamp: September 17, 2016, 12:17:51 am
content: It looks like your restoration is progressing nicely, Rob.-Pat

author: richnormand
author_rank: Unknown
timestamp: September 17, 2016, 04:09:56 pm
content: Quote from: VK5RC on September 11, 2016, 08:32:06 amI remember matching tube on a curve tracer years ago.At the beginning of life they drift a lot and then settle down. Unfortunately after a year or two of use they would age differently and redoing the matching was of benefit. Then, as emission dropped near the go/no go, the mu would be effectively out of specs and the only solution was either buying a set of matched tubes or about 25% more regular tubes than needed and do the exercise. I used to keep all of them and got some success matching end-of-life tubes also. That would usually last about an extra year.Its not as critical in many circuits, just weeding out the outliers at each end of the distribution was usually OK.Look at (for same plate voltage) grid bias and gain.

author: VK5RC
author_rank: Unknown
timestamp: September 17, 2016, 09:41:26 pm
content: Thanks for the comments, I don't have much experience with tubes but am learning , I am still some time away from 'switch on'.Currently in the process of 'stuffing a can capacitor' , the main 150, 300 and 225 v rail filter, it tested bad in circuit, was supposed to be 10uF, out of circuit was 100nF, 7k ohm dc resistance, cutting the can open and can get 3 new Nichicons inside. Getting the paper and foil out was a real pain.

author: FlyingHacker
author_rank: Frequent Contributor
timestamp: September 18, 2016, 03:57:37 am
content: While re-stuffing is the ultimate, it is also a pain. A lot of guys just clip the old ones out of circuit and put the new caps on the underside.Either way don't forget to hook up the ground on ground can capacitors.

author: VK5RC
author_rank: Unknown
timestamp: September 18, 2016, 12:04:51 pm
content: Capacitor ReStuffing, I used a drill and a sharp wood chisel (~6mm wide)3 New 10uF Nichicons (500v) with good heat shrink around it all, tested ok before stuffing (and after!) earth is connected to the can !Can cut open with cutting disk on DremelCan sealed with "JB weld" epoxy - i like it because it is quite viscous and doesn't set in 5 mins.

author: VK5RC
author_rank: Unknown
timestamp: September 18, 2016, 12:06:06 pm
content: Final Photos

author: VK5RC
author_rank: Unknown
timestamp: September 19, 2016, 06:17:16 am
content: C 751 Back in place , with notice to others

author: VK5RC
author_rank: Unknown
timestamp: September 19, 2016, 06:26:39 am
content: Brave Pill time (apologies to Jeremy Clarkson)Rechecked filter caps for ESR - OK, Fuse -holder broken so replaced, No earth leakage of note from mains active and neutral,Powered up via AC lab power supply , initially at 180v for 30 secs x2, then 210 v ,Note No Fan so only on for a minute or 2, BUTA trace !Much rejoicing. Until today wasn't sure of the status of the tube,I am sure there will be a few faults to trace etc.

author: dave_k
author_rank: Frequent Contributor
timestamp: September 19, 2016, 10:51:50 am
content: Still, aren't you glad you had the fire extinguisher handy?Great work .. can't wait to see how the rest of the restoration goes.

author: VK5RC
author_rank: Unknown
timestamp: September 19, 2016, 10:58:47 am
content: Actually I have 2 fire extinguishers - a CO2 for a small fires that I want to keep things tidy - and a dry chemical if things e.g. solvents plastics etc really get going.When I first fired it up I didn't touch the CRO, except for the tip of a DVM probe - just to make sure, I don't have a lot of faith in 60yo transformer insulation.I have had it going for a bit longer as I put the fan and ducting back in , enough to have a look at the minus 150V rail and some minor adjustments the 225v rail is quite a bit out (180v) but the 500 and other rail were spot on.

author: Cubdriver
author_rank: Unknown
timestamp: September 19, 2016, 04:46:43 pm
content: Beauteous!-Pat

author: SeanB
author_rank: Super Contributor
timestamp: September 19, 2016, 08:09:32 pm
content: Nice touch with the label there with tape holding it down.

author: steve_w
author_rank: Regular Contributor
timestamp: September 22, 2016, 05:47:27 am
content: Excellent restoration. Pleas keep up the good work.regardsSW

author: VK5RC
author_rank: Unknown
timestamp: September 22, 2016, 10:52:29 am
content: A bit of an update.She is starting regularly, going properly through the 40sec or so delay before HV, and works well for about 5-10mins, the rail voltages are a bit off and drifting a bit - not unexpected given what I think has been a long time switched off (possibly 25yrs) . the 225v rail is low (about 190v - so a problem there) All the rails should be governed by the 150v rail , the 225 is still off when all the others are spot onI have rechecked the main rails filter caps and they are still OK by ESR.She is drawing a little more power than I think she should, about 650W - should be 550W acc to manual.Below is a rough screen shot of a 2V P-P 1kHz sine wave; vertical scale OK, time base a bit fast.After bout 10mins or so, the triggering becomes intermittent then stops - so a bit of hunting required.I am looking at the current draw through the power rails, bit tricky as the schematic is a bit wrong (or later mods) and the components can be quite widely scattered on the chassis, for example the rectifying diodes are nearly 30cm away from the filter caps!Below is also a quick shot of a "warm" bit of test gear as Martin.M would say.

author: tautech
author_rank: Super Contributor
timestamp: September 22, 2016, 07:52:53 pm
content: She's looking very tidy Rob.Unlike transistor based equipment it is not safe to let the fingers do the walking over componentry to find any hot ones that shouldn't be.Is the 225V rail showing excessive ripple? Usually that might suggest the rails is overloaded and operating outside its design parameters.Is the 225V rail low immediately after power on or sags later?Is it related to loss of triggering?

author: Martin.M
author_rank: Frequent Contributor
timestamp: September 23, 2016, 02:50:18 pm
content: Martin is actually in restoration of a monster radio, very busy

author: VK5RC
author_rank: Unknown
timestamp: September 25, 2016, 11:02:09 am
content: martin ; we await with interest, a great pity I can't read German and Google translate does a lousy job of your tek blogI should have followed tautech's suggestions (which I only read this afternoon) re the 225v rail, but earlier today started followed the collapse of triggering at about 8mins after cold start up, quite a bit of tracing later I discover it was the multivibrator, which has a voltage divider and a trim pot in the middle which I can adjust and get it to trigger hot, guess what rail it uses for the top voltage rail ? Thats right the 225v. Oh well I have learnt a lot about multivibrators!I ASSUMED the 225v rail was constant-low but that is not the case I believe. I think it is dropping from about 205 cold to 185 warm and this shift is enough to destabilise the multivibrator. I have done one tube swap in the 225v regulator circuit (the 6080) the main regulator tube but no great change. The trigger stuff is all on the top shelf - so access is easy, the power stuff is mainly underneath - so a bit more tricky - still pretty careful re the "low voltage circuits" as these 100-500v rails can belt off about 200mA!All the voltage rails have minimal ripple (within 5mV) and the current draw (measured by voltage drop across the current limiting resistors) is also in specification.Checked the HV circuit and it is good at about 10,200V (should be 10k).Pictures below are a screen shot ( a sacrilege using an Agilent scope to repair a Tek I know) from the top to the bottom of the input then progressing "shaped' waves for the trigger waveform.Below is also a "warm fuzzy" shot of all those thermions!

author: dave_k
author_rank: Frequent Contributor
timestamp: September 25, 2016, 11:49:26 am
content: Nice progress! One question, is this unit old enough to have been fitted with selenium rectifiers? You may want to consider replacing them with silicon diodes, though it is not a straight-forward swap.

author: VK5RC
author_rank: Unknown
timestamp: September 25, 2016, 09:05:05 pm
content: @dave k, I think this unit has had the conversion, the selenium rectifiers were (i think) bolted to the central vertical chassis member, there are a few holes there, and a mini chassis with a series of diodes (forward drop 0.6v) with some additional power resistors, I will post a photo and a diagram of which diodes are for which power rail a bit later today.

author: Cyberdragon
author_rank: Super Contributor
timestamp: September 26, 2016, 03:12:21 am
content: Are they old diodes? They came out with "solid state rectifier" kits in the 60's so that you could replace selenium diodes. The cool thing about them is that the silicon diodes are in big sockets like fuses.

author: jh15
author_rank: Frequent Contributor
timestamp: September 26, 2016, 06:38:35 am
content: I have a 535, and a 6080 had a bad crimp and the filament was not hot enough, or maybe it was another pin, drove me crazy.Need to power it up again and impress maker spaces.

author: VK5RC
author_rank: Unknown
timestamp: September 26, 2016, 08:36:54 am
content: Interesting history re this and other 500 series beasties, mine has what i think may be called "stick rectifier" diodes in the HV supply, these are definitely clip in. They appear to replace the tube type HV diodes.Below is a photo of my 'low voltage' rectifier diodes i.e. 100 tp 500v supplies and the associated dropper resistors, it is looking in from the RHS of the unit , with the front to the left in the photo, top of the photo is up on the scope. These diodes are definitely soldered in but all are working.Below that is a Rob CAD layout of the diodes and dropping resistors (shown as a circle with a cross) on all but the 350V supply. The outermost of the dropper resistors is connected to the diodes and the innermost of the dropper resistors is connected to the series current limiter resistors usually 10ohm (on the very bottom of the unit). The diodes are in blocks of 4, and I have drawn this as a square and the positive rail is marked with a + sign on my "CAD" drawing.Had to do some other jobs around the home to keep Mrs VK5RC happy today so didn't get much time on the old girl today.

author: VK5RC
author_rank: Unknown
timestamp: September 29, 2016, 07:39:07 am
content: Looking more carefully at the 225v regulation circuit, I couldn't find any badly out of value components.Testing the circuit it did appear to try to compensate for the drop in voltage but the gain was not enough to fully compensate, on start up 215v sagging to 190v when hot.Replacing the 2 amplifying tubes in the feedback part of the 225 regulatory circuit appears to have mostly stabilised the voltage, so it goes from 215 on start up to about 209 when hot. This sag does not appear to be enough to 'upset' the multivibrator circuit in the main trigger circuit.It triggers properly on first start up and for 20 mins of running - I am happy with that.Back to a bit more of the body work!

author: silverlego3
author_rank: Contributor
timestamp: September 29, 2016, 04:54:53 pm
content: Here is a Tektronix 555!!

author: Martin.M
author_rank: Frequent Contributor
timestamp: September 29, 2016, 05:25:23 pm
content: Triple Nickel, 555it`s better to own two of them, so the one will help the other if there is a problemgreetingsMartin

author: VK5RC
author_rank: Unknown
timestamp: September 30, 2016, 06:48:02 am
content: If you have too many 555s, I would always be happy to look after one for you! HiHi.

author: Cubdriver
author_rank: Unknown
timestamp: September 30, 2016, 07:27:36 am
content: Yeah, right? A triple nickel is on my wish list too - winter's coming!-Pat

author: VK5RC
author_rank: Unknown
timestamp: September 30, 2016, 07:49:10 am
content: It is interesting that my 545 has stopped smelling of burnt dust after about 15 or so 10 to 15minute runs, there is something rattling/buzzing next to the fan, makes a racket, not that keen on poking around when switched on!

author: Cubdriver
author_rank: Unknown
timestamp: September 30, 2016, 08:10:53 am
content: Does it seem to be a mechanical vibration caused by the spinning fan, or something like a lamination buzz that's at line frequency? Do you have a chopstick, or wooden dowel,or the like? That could be something to poke around with to try to determine what's making the noise. (I wouldn't suggest a pencil, since it has that built in resistor in the middle...)-Pat

author: VK5RC
author_rank: Unknown
timestamp: September 30, 2016, 08:19:30 am
content: While avoiding the issue, (allowing me time to think about it - reminds me of the great quote "Sometimes I sits and thinks and other times I just sits" ; Chic Sale "The Specialist")I was thinking along similar lines, a bit of DRY wooden dowel with a rubber tip or fine PVC pipe (after a megger test for good measure)!

author: tautech
author_rank: Super Contributor
timestamp: September 30, 2016, 08:48:54 am
content: You're being unnecessarily cautious Rob, where's your sense of adventure?Do these old girls have a PDA supply, if not the only few hundred volts for most of the scope is not too dangerous if you are careful. Same old story, while poking around be sure to have the other hand in your pocket.As others have said, chopstick, wooden skewer, pencil (blunt end) or even a hot melt glue gun stick can suffice.If I was worried about shorting something and only had screwdrivers I'd be grabbing an electricians style one, one with insulation along most of it's shank.

author: VK5RC
author_rank: Unknown
timestamp: September 30, 2016, 09:15:37 am
content: You betcha I am cautious! (makes chicken noises!!)The 10kV supply, while measuring the voltage with my homemade/kit 20kV voltage divider, gave lovely little corona type sparks off when measuring at the middle voltage doubler diodes - I suspect due to capacitance of the probe itself. At least the 10kV supply normally has a protective cover on, The other 100-500v are all over the place and there are no covers on this puppy at present. These "Low Voltage" (the Tek term for the 100-500v supplies - it does stretch the definition in my mind) can supply several hundred milliamps and on the chassis is a warning that they can be more dangerous than the HV supply. (more chicken noises)I am not sure what PDA stands for, I couldn't find anything on a quick Google. The low voltage supplies are pure conventional linear regulated supplies, each one has its own transformer secondary, diodes, regulating circuit and filter cap. The only slightly tricky bit is the -150v supply is used as the voltage reference for all the others .I will try to sort out the noise cause it is pretty irritating at present.

author: tautech
author_rank: Super Contributor
timestamp: September 30, 2016, 09:21:30 am
content: 20kVyep that's the PDA (Post Deflection Acceleration) supply.Chook, chook, chook....I'm out of there too.

author: jh15
author_rank: Frequent Contributor
timestamp: October 01, 2016, 06:39:20 am
content: Rubber fan moubts hardened? I think I used hardware store gtommets on my Tek curve tracer.Oh, my favorite tapping tool: chopstick.

author: VK5RC
author_rank: Unknown
timestamp: October 01, 2016, 10:00:12 am
content: Thanks guys, I am still alive. Took some brave pills, tested (merger) then used a BBQ kebab type wooden stick. As surmised it is the fan, but it is the aluminium mounting that holds the fan motor. I have already replaced the rubber mounts, RS Components stock them, they are quite soft, they deform about 1mm (of 10mm) just with the weight of the fan so seem about righting my thinking. I think I might try and make a little absorbing panel from some car sound deadening adhesive sheet. I also have some thin 2mm from rubber sheet I might try first.Today was a panel day.The side panels were in pretty bad nick, a few weeks ago I took the bottom panel (Minimal fading) to a special paint warehouse and for about $90 AUD they mixed up 2 spray cans of paint to match TEK blue. It isn't textured like the original but it is matt and is a very good colour match.Today I sandblasted the panels, primed them, then top coated, I am pretty happy with the results. Photos before then sandblasted; primed and after (in next post)

author: VK5RC
author_rank: Unknown
timestamp: October 01, 2016, 10:01:28 am
content: Primed covers then top coat

author: Cubdriver
author_rank: Unknown
timestamp: October 01, 2016, 06:16:24 pm
content: That looks fantastic! Nicely done!It appears that they did an excellent job on the color matching.-Pat

author: VK5RC
author_rank: Unknown
timestamp: October 08, 2016, 03:09:13 am
content: A bit of a problem, the top support bar, to which the handles attach and the side frames interlock, on the original were a chrome plating to an aluminium alloy extrusion. This had peeled quite badly and bits (of conductive!) chroming flakes were found in the scope. Sandblasting removed it all.A quick trip to my local "Plating" company confirmed that plating to alloys is not good. I note that on some later Tek models the top bar is painted the same colour as the sides - so that is what I decided to finish with.I also got some acoustic padding from Jaycar (used for car door lining etc) and padded the fan frame, it dropped the noise quite a bit.Results below.

author: VK5RC
author_rank: Unknown
timestamp: October 08, 2016, 03:27:21 am
content: Attention to the front knobs etc took the form of Meguiars PlastX applied with a cotton bud to get in the slots of the knobs and then a quick finish with Armourall which leaves a nice shiny finish.The scope had a few final adjustments and below is shown displaying a 1MHz sine wave ( the 'limit' of the plug in).And a final shot.Rough costs AUDScope $80Tubes x3 ~ $50Paint (spray) $150Fuse Holder $10Caps (Electro) $15fan Vibration Mounts x3 $15Various; Cotton buds (about 500!) , IPA, window cleaner, brushes, distilled water, rags, silver solder. car polish, silicon oil, L&P gun oil. simchromeThanks to EEV blogers including EEV Dave, Martin.M, robrenz, tautech, cubdriver, Sue just to name a few , by sharing your knowledge I have gained a lot of confidence and am thus able to tackle projects like this. I have learnt a lot. Thanks guys. If any questions re what I have done please ask, happy to share what I did.

author: Cubdriver
author_rank: Unknown
timestamp: October 08, 2016, 03:29:44 am
content: Beautifully done, Rob - it looks brand spankin' new!(Makes me want to do the same to the 575 curve tracer I got last year...)-Pat

author: tautech
author_rank: Super Contributor
timestamp: October 08, 2016, 03:44:13 am
content: Quote from: VK5RC on October 08, 2016, 03:27:21 amKinda knew you'd come up trumps with this one Rob so I added it to this other thread (don't know who started it)https://www.eevblog.com/forum/repair/vintageclassic-renovation-techniques/msg1036368/#msg1036368Nice work, thanks for sharing.

author: VK5RC
author_rank: Unknown
timestamp: October 08, 2016, 06:08:44 am
content: Thanks guys, the problem when you get these beasties is you don't know what could be wrong and getting 'that' part may be impossible because it was the dodgy part and everyone else has ripped it out of any 'parts units'.Now cubdriver a 575 is a really lovely device, definitely worth the effort.While pulling it apart I found it at one stage the 545 belonged to an interstate University dept, I am going to send the completed photo and a quick description of the repair to the Department tech officer for a laugh - see if I get a response.

author: Cubdriver
author_rank: Unknown
timestamp: October 08, 2016, 07:03:47 am
content: The 575 will definitely need some serious scrubbing to pretty it up, but it is at least somewhat functional based on some quick testing I did on it last year. I finally got back into the Electro Instruments DVM tonight and at least cut all the new isolation mounts to length. I've been putting that one off for far too long.And I have to say, I'm still amazed at how clean your scope came out. If I can get the 575 looking half as good I'll be pleased.-Pat

author: VK5RC
author_rank: Unknown
timestamp: October 08, 2016, 07:20:23 am
content: I had quite a bit of luck but Tek made good panels with lettering 'in deep' and good knobs of a sturdy plastic. Good manuals and not weird components in that vintage.Nothing like putting it up on EEVblog to make you push it along!I am still so envious of what you guys can get in the USA, so many sellers won't post outside the USA, but it might save me quite a bit of cash and space! HiHi

author: TheSteve
author_rank: Unknown
timestamp: October 08, 2016, 07:41:54 am
content: Without a doubt I think we can all agree that it is now "A thing of beauty and a joy forever" - amazing job!

author: Cubdriver
author_rank: Unknown
timestamp: October 08, 2016, 08:05:26 am
content: Quote from: VK5RC on October 08, 2016, 07:20:23 amMy understanding is that the markings on those old panels are actually part of the anodization, rather than being silkscreened on as they are on many other instruments. Because of that, they're pretty bulletproof shy of gouging the panel to the point the anodization is scraped off.They were definitely very sturdy and well made devices. It would be interesting to see how much of the plastic fantastic stuff of today will fare over the coming years.It's a bummer that your options are so limited due to the international shipping issues, but you are correct in that it is likely saving you considerable money and space. Trust me on that one!-Pat

author: VK5RC
author_rank: Unknown
timestamp: October 08, 2016, 09:33:47 am
content: Interesting re anodising, I have not had a look at the panels up close with a microscope but the lettering does seem extremely tough.I must be patient, the 545 was a 20min drive away, so stuff does come up from time to time. :-)

author: med6753
author_rank: Super Contributor
timestamp: October 08, 2016, 11:23:26 am
content: That scope is beautiful! Nice job!

author: pelule
author_rank: Frequent Contributor
timestamp: October 08, 2016, 11:51:55 am
content: Nice job!

author: richnormand
author_rank: Unknown
timestamp: October 08, 2016, 05:05:10 pm
content: Excellent job indeed! Congrats.One thing that intrigues me is that mine has a small compartment (6" x 4" about 3/4" deep) on top with a door that pops out in the right hand side of the right cover (over the timebase controls). It's perfect to put in bnc adapters and such. Your does not seem to have that. I can post a pix if interested.Second this is that I located my watt-meter. You were worried about overall power consumption at one point. I could hook it up to mine if you have not resolved that issue.Keep up the good work. What will be your next restoration project?

author: VK5RC
author_rank: Unknown
timestamp: October 08, 2016, 10:53:11 pm
content: @richnormand , interesting re the little storage box, I have seen some photos with a lid in that area and wondered (till now). Would be useful. There do seem to be a lot of variances in these units, e.g. varied HV diodes can be either silicon or tubes, the LV rectifiers - at least two different versions.If you could measure your power consumption it would be interesting.Later today I will fire mine up and put up the true power, VA etc.When having a good look at the unit, measuring the DC power consumption, (by measuring voltages across the current limiting resistors on the "low voltage" 150-500v supplies) the consumption figures look ok. i wondered whether it is due to the issue that I am running at 235v and I think it was really made to run at 115v.I have run it as long as an hour without trouble - so i am reasonably happy things are 'ok' - it is an old unit so things will pop up from time to time.I have a bit of old gear and on the first of the month I try to switch on all my gear for 10-15mins (not all at the same time), my postulate is that might keep ageing electrolytics a little happier for longer and also if something doesn't work, I find out before I need to use it.Re next project, is either1 An HP 5221 with one dead digit (MSD), real problem is the nixes in them are really hard to find, but i am not sure it is the nixie or the driving circuit yet.2 My 5245L, if I recall the plug in was a bit dodgy and I have ordered an "AS IS" 5261 plug in, so I might have a bit more of a go at the 5245L and its plug ins.I am seriously running out of room so have to be careful with purchases!I have to tell a funny story, while showing my completed 545 to my 19yo daughter, she went out to my 'shack' rolling her eyes as only a 19yo can, when she switched it on, and as the tubes started to glow etc , she actually said 'wow that's cool' . She would deny it now, but for a second or two she was interested. My 12yo just said "are you going to sell it?"Regards Rob

author: tautech
author_rank: Super Contributor
timestamp: October 08, 2016, 11:07:30 pm
content: KidsI'm sure they all think we're nuts, until they need something fixed.Then it's bata time....what will they do in return?

author: VK5RC
author_rank: Unknown
timestamp: October 08, 2016, 11:23:19 pm
content: As the only male in a household including 3 teenage daughters ……… no commentPower data, on start up then full power, with calibration unit on.

author: richnormand
author_rank: Unknown
timestamp: October 09, 2016, 12:51:58 am
content: Quote from: VK5RC on October 08, 2016, 10:53:11 pmMy daugther first word was "scope". She loved to play with it and see the traces..... That was sooooo many years ago...

author: Cubdriver
author_rank: Unknown
timestamp: October 09, 2016, 03:38:59 am
content: The good thing about the 5221 is that the tubes are socketed, so isolating the issue should be relatively simple.-Pat

author: Cubdriver
author_rank: Unknown
timestamp: October 09, 2016, 03:41:23 am
content: Rob -You need to build a nice vacuum tube amp for the 19 YO.-Pat

author: VK5RC
author_rank: Unknown
timestamp: October 09, 2016, 05:11:00 am
content: Pat the way she treats phones, she needs something WAY more robust. I now consider myself an expert on replacing iPhone screens, my eldest's tally is 2 iPhone screens, one back cover, one went swimming and one laptop LCD screen!!!!! I am not kidding.She would need an amp made of those ICs that can handle being fired in a missile and a fully potted PCB with hostile environment input, output and mains protection, actually come to think of it - this is a marketing opportunity for her and her friends who seem to have similar electronic handling skills. (HiHi)Rob

author: Cubdriver
author_rank: Unknown
timestamp: October 09, 2016, 05:57:43 am
content: Rob - that is a dreadful trail of electronic destruction that she's left in her wake, but I was thinking more along the lines of a big honking home stereo amp, with a heavy power transformer, choke and two beefy output trannies. Not exactly portable. Though I suppose for the younger generation, the home stereo has by and large gone the way of the dinosaur and the dodo so something like that probably wouldn't be of much interest to her, would it?As for portables, bear in mind that proximity fuzes with vacuum tubes were fired from naval guns in 5" AA shells in WWII, so it's quite possible to make tube gear that's at least slightly more robust than an iPhone...-Pat

author: Cyberdragon
author_rank: Super Contributor
timestamp: October 10, 2016, 09:44:36 pm
content: Iphones are crap for durability. Androids can be waterproof and shatter resistant. You can get high impact screen protectors that can withstand hammering though.