Tek 222 Portable Scope Schematics? - Page 1
Forum section: electronics / testgear

author: timb
author_rank: Super Contributor
timestamp: October 09, 2014, 11:53:54 am
content: Hey guys, anyone have a copy of the *real* service manual for the 222 (or even 222A) they could share? I've already got the "User Manual" you can find via Google, which isn't super helpful because they don't include the schematics.Thanks!Sent from my Smartphone

author: tautech
author_rank: Super Contributor
timestamp: October 09, 2014, 12:27:20 pm
content: I haven't downloaded this to check for schematics however the front page does say Service manual.http://elektrotanya.com/tektronix_222_sm.pdf/download.html

author: timb
author_rank: Super Contributor
timestamp: October 10, 2014, 08:13:09 am
content: Quote from: tautech on October 09, 2014, 12:27:20 pmNo, sadly that's the "User's Service Manual" where they go out of their way to talk about specific components and designators, without actually providing a schematic. *Sighs*Sent from my Smartphone

author: Andy Watson
author_rank: Super Contributor
timestamp: October 10, 2014, 08:49:17 am
content: Try emailing Dave at artek. There are several 222A service manuals around, but only artek had the full schematics.http://artekmanuals.com

author: iDevice
author_rank: Regular Contributor
timestamp: October 11, 2014, 01:23:11 pm
content: Most of my manuals are bought from Qservice.I don't even bother to download the free ones when available anaymore because they are mostly very poor scans where the schematics are spread over multiple pages and with such a low resolution that components values are sometimes unreadable.Qservice manuals are professional full page scans (even the folding schematics) with post treatment to clean the smudges.Well worth the (somewhat high) price in my opinion.The 222 you are looking for ishereas a full library but each manual is also usually separately available.Hope this helps.

author: timb
author_rank: Super Contributor
timestamp: October 12, 2014, 07:50:04 am
content: Yeah, that doesn't have the schematics, iDevice. That service manual is the same as the one linked above.I ended up contacting Dave at Artek, who told me he's never seen a real service manual for the 222 in 15 years of selling manuals.He said that he's been told the 222A is very similar and if that manual didn't help me, he'd give me a full refund. So I bought the 222A manual.I just got the 222 open tonight, so we'll see tomorrow how similar it is.By the way, my problem is that the screen is really dim. Upon opening the thing and pulling out the -1500VDC board, this is what I find directly under the intensity control pot:The pot itself is also really wiggly.I'm guessing something went horribly wrong there and that's my issue. Unfortunately I don't have any means to measure that kind of voltage, short of building a resistor divider I guess...Sent from my Smartphone

author: iDevice
author_rank: Regular Contributor
timestamp: October 13, 2014, 09:11:55 pm
content: Well all service manuals I ever bought from Qservice have always included schematics.I couldn't swear for the 222 of course because it's not part of my collection but the 224 is and I have the schematics in section 9.What makes you think the 222 manual doesn't have the diagrams ?

author: timb
author_rank: Super Contributor
timestamp: October 13, 2014, 11:00:46 pm
content: Because the pages in their preview are identical to the Service Guide you can find via Google.Sent from my Smartphone

author: Andy Watson
author_rank: Super Contributor
timestamp: October 13, 2014, 11:35:24 pm
content: Quote from: timb on October 13, 2014, 11:00:46 pmThat is exactly my experience in searching for 222A circuits. I was eventually led to artek via a discussion on the tektronix yahoo group.

author: timb
author_rank: Super Contributor
timestamp: October 14, 2014, 01:46:55 am
content: Quote from: Andy Watson on October 13, 2014, 11:35:24 pmAs it turns out, the 222A schematics are pretty close to the 222, at least for the HVDC board. In the end, I’m pretty sure the tube is bad because after powering the thing up for the first time, I was getting a dim display, then nothing. I’m thinking something broke in the tube during transit. (Yes, I checked all the connections.) So the seller is giving me a refund.

author: Andy Watson
author_rank: Super Contributor
timestamp: October 14, 2014, 10:20:52 am
content: Quote from: timb on October 14, 2014, 01:46:55 amDid you check that the pins in the tube socket were mating with the pins on the tube?My 222A had a problem with brightness - no control. The fault was with the grid-pin on the tube socket. Over time the metalwork in the socket had retracted into the body of the socket and was no longer making proper contact with the tube. There was enough capacitance to hold the grid and make it look functional, but without the DC path the brightness was all over the place.

author: Martin.M
author_rank: Frequent Contributor
timestamp: October 18, 2014, 01:28:41 pm
content: when u think a 222 CRT is damaged put it simply in the X-Ray to see what is the matter with the little screenthis is a deflection plate...

author: alhoop
author_rank: Contributor
timestamp: November 04, 2014, 02:14:06 am
content: Quote from: timb on October 14, 2014, 01:46:55 amYeah Tim I am that seller. I thought you said you just opened the unit and closed it right back up. A little disingenuouswere you not. did you see the photo I sent you of a trace where you said there was none. If you can live with it........Al

author: timb
author_rank: Super Contributor
timestamp: November 04, 2014, 05:24:16 am
content: Quote from: alhoop on November 04, 2014, 02:14:06 amWelcome to the EEVblog.When I said there was a missing trace, I was talking about the broken trace on the HVDC board that is fitted with a bodge resistor on the backside (where I might also add it looks like there was some kind of short circuit based on the nearby charring).After I sent you the message requesting a return and you had some hesitation due to it having been opened, I decided to investigate further, found the resistor (which was bad, I might add) in addition to two bad pots, all of which I fixed and it made no difference. So you’re welcome for that, by the way.The display only ever briefly worked for me. I saw it one time for about 5 seconds, that’s it. If you’re saying the tube wasn’t connected when you got it back, I most likely didn’t push it in tight enough and it came loose during transit.If the display is working for you full time now, then there’s clearly an intermittent issue.I don’t know why you’re so insistent on calling me a liar. You got your scope back in better condition that it arrived. You said yourself the probes are worth “$180 each” so either resell the scope or the probes or whatever. The transaction is over. Geeez.If you’re saying the tube was disconnected

author: alhoop
author_rank: Contributor
timestamp: November 04, 2014, 01:35:46 pm
content: Quote from: timb on October 12, 2014, 07:50:04 amTim:This is what I use to measure HV on these small scopes. Notice it goes to 2.5KV DC.http://www.ebay.com/itm/VINTAGE-MIDLAND-23-101C-Volt-Ohms-Milliammeter-in-BOX-/221591280268?pt=LH_DefaultDomain_0&hash=item3397de9a8cDon't worry, I'm not the seller - besides I have you blocked.Al

author: timb
author_rank: Super Contributor
timestamp: November 04, 2014, 01:42:37 pm
content: ...alright? I'm sorry I dishonored your family or kicked your dog or whatever the hell I did to make you so obsessed with me.We had an eBay transaction they didn't work out. You got the item back in as good or better condition than it was sent originally. I got a refund and paid return shipping. Transaction over, okay? This is not normal behavior.Christ on a fucking cracker.(By the way, I am familiar with high voltage; I used to have a bunch of gear including scope probes but it went missing after my move earlier in the year.)Sent from my Smartphone

author: alhoop
author_rank: Contributor
timestamp: December 18, 2014, 11:19:16 pm
content: To Tim etalSupposedly the schematics for the 222 were never released by Tektronix - probably considered proprietary -the attached drawing shows the only differences I could find between the two on the High Voltage PowerSupply which was the object of our attention.Tim, the bodge resistor - what ever that is - was R474 and R478 added, photo shows where trace was cut tothe Intensity pot to allow the addition.A FINE LITTLE SCOPE!!Tim you should take it easy on that cracker - I imagine it is getting soggy.Al

author: alhoop
author_rank: Contributor
timestamp: December 19, 2014, 07:32:31 pm
content: BTW QService states this concerning the 222 manuals:" AS WITH ALL NEWER TEKTRONIX MANUALS SERVICE MANUALIS FOR MODULE REPLACEMENT LEVEL ONLYNOT FOR COMPONENT LEVEL REPLACEMENT"Al

author: Fraser
author_rank: Super Contributor
timestamp: December 19, 2014, 08:32:32 pm
content: An interesting little thread for me. I own several of the mini Tektronix scopes including the 211, 212, 213 and 222A.It was a pity that the 222 in this thread failed but at least it was a simple fault that did not involve some rare IC.My view of the 'dispute' that appears to have occurred in this thread is that if a unit arrives DOA or with an intermittent fault, the buyer MUST contact the seller BEFORE opening the case. Failure to do so invites refusal of a refund no matter how harmless the activity may have been. I have done this on occasion and have yet to be refused permission to look inside for obvious transit induced faults. I also advise the seller of my skill-set and responsibility for any damage I cause.I am a long term ebay buyer, and sometimes a seller. Having spoken to many sellers in recent years it is very apparent how many unpleasant people buy on ebay. Many sellers warn that they seal and secuity mark their products. The reason ? Their are many cases of buyers stealing or swapping parts out of a unit to repair their own faulty unit or deciding they do not like the unit and deliberately placing a fault on it as an excuse for a refund. I am NOT suggesting that anything wrong occurred in this transaction BUT it may explain why a seller is concerned aboiut refunding a unit that has been opened by a buyer.I sold an ICOM R7100 receiver to a chap in Scotland. When it arrived it did not receive anything. The buyer reported the issue and asked me if I had another or could repair the unit. He obviously trusted me and wanted a mint condition R7100 at a reasonable price. I received the R7100 back from teh buyer and sadly he had left the lifting bale in the up position causing damage to it and the underside of the receiver. The fault was the 10.245Mhz crystal. I bought an original ICOM replacement crystal. Fitted it and fitted a new Bale and lower case cover. I carried out a full specification check and frequency calibration of the receiver and it performed flawlessly. The buyer was overjoyed with the receiver and the repair work that I had carried out. I never told him of the transit damage caused by hos error with the Bale. I trusted him and he trusted me. On this occasion we were two gentlemen of good morals. That is not always the case sadly.If you receive a DOA I strongly recommend discussing options with the seller BEFORE doing any investigation or repair work. It keeps everybody happy and avoids misunderstandings. The seller may even volunteer to repair the unit at no cost....as was the case with my R7100 sale.Oh and that blackening on the PCB is unlikely to be charring. A rub with a finger will normally remove it ! The high voltage attracts dust to the PCB and such a sight is very common inside TV's and oscilloscope high voltage boards. The dust is convected dirt so is often black. A pcb that has suffered arcing on the surface or within looks quite different. I speak from experience.Aurora

author: alhoop
author_rank: Contributor
timestamp: December 19, 2014, 11:19:01 pm
content: Quote from: Aurora on December 19, 2014, 08:32:32 pmHello Aurora:The unit never failed, just had a dim trace.I sold the unit "for parts only" because of the dim trace. I think the buyer overestimated his abilities. These units can beintimidating especially if no schematic is available. By hook or crook I obtained a schematic, one that had the Tektronixpart # for each component listed beside the component,ie no parts list. R474 and R478 were not in the original unitbut were added later, that's what the resistor in question is. And no, as you stated the board is/was not charred.Don't know why Tektronix never released the schematics.I am somewhat intimidated by the charge pump oscillator in the 221. Do you know how to disable the transformer feedbackfor troubleshooting purposes?RegardsAl

author: Fraser
author_rank: Super Contributor
timestamp: December 20, 2014, 12:06:02 am
content: Sorry, I am no expert on the 221 internals. Mine is working fine so I have not been inside it yet.I had not realised that the unit was sold by you as "S or R". You are obviously a very honest seller and declared the unit as having an issue. Pretty fair to buyers in my opinion. I have bought many spares or repairs equipments, and repaired them as fun projects. I have found most TEK equipment that I have worked on to be a pretty unpleasant experience. I dislike their power supplies. Later (pre DSO) scopes seem worse than earlier offerings in this respect though.I hope you find a deserving home for the little 221.....they may be old and have a relatively small bandwidth but their safety isolation and good design is welcome in my lab anytime.Aurora

author: harrimansat
author_rank: Regular Contributor
timestamp: April 12, 2015, 06:43:58 pm
content: Quote from: alhoop on December 19, 2014, 11:19:01 pmHi, do you have to fix a 221 power supply? Few months ago I fix mine, rewinded transformer and put a litthium battery:

author: harrimansat
author_rank: Regular Contributor
timestamp: April 12, 2015, 06:55:45 pm
content: Quote from: alhoop on December 19, 2014, 11:19:01 pmHi Alhoop, do you have a 222 diagrams??? not 222ACan you please send me a copy?Thanks

author: alhoop
author_rank: Contributor
timestamp: April 24, 2015, 04:22:17 pm
content: Quote from: harrimansat on April 12, 2015, 06:55:45 pmI do have the 222 diagrams(not 222a) but I had to swear that I would not divulge them to anyonein order to obtain them. What part in particular are you interested in? I might be able to send youa schematic of say the Power Supply.Interesting job you did on rewinding the Charge pump transformer. I have found two bad L610 dual inductors(open)and am replacing them with 12 millihenry 400 milliamp inductors ( original was dual 30 millihenry 300 millamp ones).You might try contacting these people - thay sell a lot of Tektronix manuals( the one for the Tektronix 222 statesthat it is not for troubleshooting at the component level.http://stores.ebay.com/Qservice-tech-shopRegardsAl Hooper

author: vivaT
author_rank: Contributor
timestamp: October 29, 2018, 08:37:25 am
content: Ive uploaded the service manual including schematics to eserviceinfo.You can find them herehttps://www.eserviceinfo.com/download.php?fileid=70093

author: Satbeginner
author_rank: Regular Contributor
timestamp: October 28, 2019, 04:49:40 pm
content: Hi all,I just got home from a long trip and did not have time to open my 222, but in the meantime on the TekScopes group an experienced user sent in this file.I am not sure it has everything, but it has a lot.I will try to add it to this message.As attachment it was too large, but here is the original link:http://www.hakanh.com/dl/temp/222_Component_Level_Service.pdfUn saludo,Leo