Replacement  for   CRT? - Page 1
Forum section: electronics / testgear

author: 440roadrunner
author_rank: Contributor
timestamp: February 14, 2014, 12:17:50 am
content: Hi, hope you young pups can teach an old dog new tricksI have a Motorola same as R2001D or R2008D "communications systems analyzer" commonly known as a "service monitor" While still usable in the shop, the CRT is getting dim. These CRTs are proprietary, were available only from Motorola at great cost, and were evidently only manufactured by either Telefunken or Magnavox, and sold only to Motorola under Motorola part numbers. They are no longer available, unless you score, say, a parts unit on th' BayI guess my question is twofold:A.....how can I find a more common CRT substitute, perhaps with circuit changes, andB....Is there a flat panel device I can sub, even if it must be outboard?It seems to be difficult to find a substitute, first, physical limitations, and many OTHER tubes such as Tektronix seem to also be proprietary, so finding specs for THEM it tough.This is fairly common as analog CRTs go......intensity input (z) for character and other special video display, and common X-Y amps for vertical / horiz. functions.So things like these there new fangled digi scopes, none I have found have a Z (intensity modulation) input.Anybody have ideas on a work around for this?If any of you have ideas, I did remove and measure the CRT size, and have some of the circuit voltages. Motorola is sparing about this in their service manual.Thanks for yer help

author: PaulAm
author_rank: Frequent Contributor
timestamp: February 14, 2014, 12:58:15 am
content: If the tube is getting dim, but other wise is OK, you can get some extra life out of it by using a CRT rejuvinator like a Sencore CR70. Essentially, you use up the top of the cathode layer that emits electrons. The rejuvination process strips off some of that restoring the cathode efficiency. You can get another 1000 hours or more of life that way. Eventually you run out of cathode material and the tube is junk.You can find Sencore CR70s for around $50 in the US.This problem comes up with Spectrum Analyzers a lot since they are typically left on continuously. Whether or not you can use an LCD replacement depends on what kind of signal is driving the CRT. Some LCD replacements are available for HP SAs, but they run around $1500 or so. Your odds of finding an off-the-shelf solution are not good.I like the CR70, it was built to minimize the possibility of damage to the crt, but it you want to see what you can do with equipment at hand, take a look here:http://www.ke5fx.com/crt.htmlThat page has some good links on CRT restoration.

author: dr.diesel
author_rank: Super Contributor
timestamp: February 14, 2014, 01:04:58 am
content: Picts of the Plymouth or foul play....

author: 440roadrunner
author_rank: Contributor
timestamp: February 14, 2014, 01:36:44 am
content: LOL. I haven't had the 440 Road Runner for a very long time. Here:http://moparforums.com/forums/f62/my-old-ride-back-day-596/These days I have an old Dart. It's currently apart for paint. My neighbor talked me into this, I ended up having it media blasted. I hope to be back on the road (if not completely finished) again this summer. This photo was taken late this summer This is a low budget back yard Craigslist car. Seats, rear axle, engine/ trans, wheels, everything is "off CL" Had a warmed up 318 this summer, will have a mild 360LA and hope to add a single turbo.Tear down for paint...........http://www.forabodiesonly.com/mopar/showthread.php?t=255877Last part of front disk conversion. With a 9" Ford (Linc Versailles) rear axle, this thing has 4x disk brakeshttp://www.forabodiesonly.com/mopar/showthread.php?t=248634"As finished" this summer. 318, TBI Holley injection, headers, 3.7x rear axle, manual VB A-727, it's plently snotty. 65--90 is just a stab of the gas away, maybe 3 seconds. REALLY stops and handles nice. I bought a parts car shell which ended up having some VERY large torsion bars. Now has 73/4 front K and sway bar, and added leafs in the rear from a second set of rear springs.

author: dr.diesel
author_rank: Super Contributor
timestamp: February 14, 2014, 11:19:18 am
content: ^ Awesome!Sorry, not many car guys around here and just had to ask with a username like yours!

author: GreyWoolfe
author_rank: Unknown
timestamp: February 14, 2014, 03:52:32 pm
content: What is the saying? MOPAR or NOCAR?

author: 440roadrunner
author_rank: Contributor
timestamp: February 14, 2014, 06:59:39 pm
content: Quote from: GreyWoolfe on February 14, 2014, 03:52:32 pm'S alright. Last night I tore into my old Tek 475 enough to find that it's CRT is way too long, regardless of operating voltage, to fit the Motorola. This is a disappointment, as there are always a fair number of tek CRTs on th'Bay In addition, this particular CRT has separate deflection plate connections out of the socket. That in itself would not have been a deal breaker.The search goes on.

author: PA0PBZ
author_rank: Super Contributor
timestamp: February 14, 2014, 07:17:45 pm
content: One trick I used to get old crt's to live a bit longer is to increase the filament voltage. With old tv's that was easy because they where mostly powered by a separate winding on the hv transformer, so an extra turn used to do it. Not sure about your Motorola of course.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 14, 2014, 07:31:16 pm
content: I'm pretty I've seen a general purpose module somewhere to drive a flat panel from a wide range of obsolete video formats.

author: N2IXK
author_rank: Frequent Contributor
timestamp: February 14, 2014, 08:03:45 pm
content: I think this is more akin to an oscilloscope CRT, so there isn't a real "video format" to convert from. Just X and Y deflection voltages, and intensity modulation on the Z axis. Every service monitor I have seen used an electrostatic deflection tube, not a magnetic deflection, raster scanned type.The flat panel LCD conversions are easier to do in raster scan applications like CNC controllers, or Dave's HP signal analyzer a while back.

author: 440roadrunner
author_rank: Contributor
timestamp: February 14, 2014, 11:12:25 pm
content: Quote from: N2IXK on February 14, 2014, 08:03:45 pmThis is correct. The CRT and amplifiers use conventional analong o'scope "thinking" IE Z azis and XY plates. Because I'm not up on modern O'scope technology and displays, I'm not sure what I can do. The reason I need Z is because this thing displays a lot of functions in graphics and menus and so on I don't think there is what you might call "composit video" anywhere in the device. I don't know enough about video systems to figure out how to work around it

author: woodchips
author_rank: Frequent Contributor
timestamp: February 14, 2014, 11:22:16 pm
content: What are the dimensions of the CRT? What are the X, Y and Z bandwidths? What sort of deflection voltages are used?The alphanumeric display CRTs are typically 5MHz bandwidth, also very often standard CRTs with no PDA so fairly low sensitivity, V/cm deflection.I am assuming it is electrostatic?Easiest fix is to simply use something like a 7603 with suitable amplifiers, 7A18 will do, to act as two differential inputs for X and Y. A third amplifier should do the Z. The 7603 (or whatever) has a large 12x10cm screen, whether that is large enough who knows. If you get lucky there is the HP 134S large screen scope.

author: AMR Labs
author_rank: Frequent Contributor
timestamp: July 03, 2016, 06:09:43 pm
content: Old thread but that not withstanding here is some info that might be useful on how to hook up an external scope to the R2001D to use as a screen substitute. I found this information on the Batlbs forum some time ago, but have not personally verified it. I only made a small correction bellow.http://batboard.batlabs.com/viewtopic.php?f=1&p=203332&t=42545Here is how I have connected an ocilloscope to the R2001.The 'scope is used as a replacement for the CRT.The scope must have X,Y,and Z inputs.X=VerticalY= EXT Horizontal input.Z= Blanking input, which is often found on the back panel of the scope.The video will be inverted (negative) unless you construct a simple video inverter.Connections to the R2001:All connections are to test points on the A-2 board which is next to the CRT. The test points are in order as noted.Also note that the LV supply will not operate with out the HV supply connected..R2001A,B,C.Vert: TP4Horz TP1Z (video) TP8TP1 is toward rear of the chassis.R2001D:Vert: TP1Horz: TP6Z (video) TP 1 --> my correction: should say TP7TP1 is toward the front of the chassis.Set the scope for ext horz, set vert, and horz gains for the desired scan.Adjust scope intencity, and 2001 intencity for adequate display.The only R2001 front panel control which will be inop is the Focus.

author: helius
author_rank: Super Contributor
timestamp: July 03, 2016, 06:50:42 pm
content: Quote from: PaulAm on February 14, 2014, 12:58:15 amThe CR7000 (according to Sencore) is safer on newer or high-resolution displays because it has some restore cycles that are more gentle. It's also prohibitively expensive compared to the CR70. Has anyone modified their CR70 to lower its beam current?

author: ve3id
author_rank: Newbie
timestamp: June 26, 2022, 05:52:25 pm
content: I just saw this as I was looking for a solution to the same problem.I have a Motorola R2001D/HS that looks like it may need the monitor replacing soon - has anybody found a solution?Yes, I have confirmed from the manual that it uses X,Y, and Z outputs from card A2 in the service monitor.I'd love to find a way of putting an LCD in there!73 de Nigel ve3id

author: AMR Labs
author_rank: Frequent Contributor
timestamp: June 26, 2022, 09:36:02 pm
content: Quote from: ve3id on June 26, 2022, 05:52:25 pmWhat are the symptoms of your CRT? Have you checked what brand your R2001D has? It seems the american made one (Magnavox) is the worst offender. The AEG/Telefunken rarely seem to have any problems unless really at end of life. Also some persons report that rejuvenating seems to prolong useful life as well. Not sure if that applies to all 3 brands of CRT.Mine behaves quite well with decent intensity and focus stops drifting after about 5 minutes of warm up, so still quite usable.Also during warm up if I turn down the intensity the screen background actually lights up, if I go up on intensity then the characters actually get somewhat brighter but loose a bit of focus as well.There seems to be a middle ground setting that works best, and that point also drifts a bit until the whole thing warms up properly.LCD, I don't think so far there is anything out there that can be used as a direct replacement, but have not checked for some time. Wish someone would come up with one that works decently and preserves the resolution and screen reaction time of the measurement bargraphs. Nothing like the good old CRT.

author: TomKatt
author_rank: Frequent Contributor
timestamp: June 28, 2022, 12:28:56 pm
content: Just an idea to cover worst case scenario of original crt inoperative and no replacement available... You could work your way back up the XY chain to the lower level analog signals (instead of the high voltage plate drivers) and use an oscope to display the vector signals. I owned an Atari Tempest game for a while and was able to play the game on my scope by that method. You'll need a decent analog CRO in XY mode for this to work, digital scopes don't process XY fast enough. I don't believe I've ever seen any type of vector to raster converter, so it's unlikely you could substitute an lcd display panel in that gear.

author: ve3id
author_rank: Newbie
timestamp: June 28, 2022, 12:45:39 pm
content: Thanks TomKatt and AMR Labs,The only symptom I am seeing so far is jittery screen position, and yes, I know this is most likely a dirty pot. However if I am going to open it up I want to be pro-active and replace the CRT since I want to get many more years from this.The A2 card, somebody previously said, does have low-level X,Y,and Z signals that could drive something if I can find an LCD that can work from them!As far as scoping with an analogue scope goes, that might be an adventure since its own display was fading when I put it in the back closet and bought a Keysight digital scope a few years back!I was really hoping to find somebody who has done it! There is one co I found that specialises in replacing CRTs in industrial panels but I think their prices would be more that a new CRT!

author: TomKatt
author_rank: Frequent Contributor
timestamp: June 28, 2022, 12:51:24 pm
content: Quote from: ve3id on June 28, 2022, 12:45:39 pmI believe you will find that any CRT conversion is based on raster type displays... It's nigh impossible to convert vector signals to raster format needed for lcd panels.I play around with vector stuff pretty frequently - I'll keep an eye out for any possible CRT's that might fit your application.EDIT - poking around the interwebs I discoveredhttps://wiki.w9cr.net/index.php/Motorola_R2001D#Scope_conversion, which lays out how to use a scope as a display for the R2001D. In addition to an analog CRO, gear like old Tek vector monitors used to be cheap and available on eBay - these work equally well, if not perhaps better.

author: AMR Labs
author_rank: Frequent Contributor
timestamp: June 28, 2022, 01:24:18 pm
content: Quote from: ve3id on June 28, 2022, 12:45:39 pmThe problem with the CRT usually involves the trace getting very dim, so if yours has no problem there, your CRT should be fine. Besides you cannot just replace the CRT very easily, you have to find one first which is very difficult (and expensive). If you find one just keep it on hand until its needed. Over the years I've seen them come up sometimes but very rarely. Now regret not having purchased one of those as a spare back when. In any event its a good idea never to leave the screen idle for long periods of time, if you need to keep the service monitor powered on then just turn down the intensity to zero and that will save you CRT life.Is the CRT position jittery only when you turn any of the screen related controls? If so the controls just might need a bit of lubrication/cleaning, which is not uncommon in this instrument. Do not use contact cleaner on the potentiometers, use Deoxit fader lube (light green liquid). Also do not use Deoxit red, that is meant for switch contact cleaning. If CRT position is jittery by itself, perhaps the CRT power supplies may need some attention. Lube the pots first, or sometimes by just excercising them a bit cures the problem by removing any oxide that might have formed on the track or contact finger. As I remember getting to the pots involves removing the whole front panel which is a job in itself. I still have to replace the RF Scan control in mine which sometimes works, most of the time it does not, but I have a spare encoder. One of these days will get to it.The detailed instructions on how to adapt a scope as a display alternative are in one of my previous posts above, and also a link to the original post at Batlabs.

author: TomKatt
author_rank: Frequent Contributor
timestamp: June 28, 2022, 01:34:16 pm
content: Quote from: AMR Labs on June 28, 2022, 01:24:18 pmI somehow missed that - you are 100% on point... CRT tubes are fairly basic and provided the filament and gun are in decent shape (as demonstrated by a bright trace), most of the time any jitter or distortion is a result of the signal processing driving the tube. In some cases, even a dim display is the result of bad signals and not the tube itself, so you can't make assumptions without testing.Tubes seem to get a bad rap in terms of "wearing out", but in many cases they can outlive solid state components. I've got an old Waterman scope from the 1940's that is still working using the original tubes. And if you've ever watched Youtuber Shango066 pull a vintage tube tv out of caked desert mud and get it to display video with just some minor tweaks, you begin to really appreciate the hardiness of vintage tech.

author: AMR Labs
author_rank: Frequent Contributor
timestamp: June 28, 2022, 01:49:43 pm
content: Quote from: TomKatt on June 28, 2022, 01:34:16 pmThe problem usually with the CRT wear on the R2001D is that the service monitors where usually powered up all day from morning to evening at the service shop regardless if they where used or not, so that is the reason many have weak CRT's, but other than that this model seems pretty much bullet proof. Its really the type of use the tubes see, I bet your old scope does not see too much use anymore, so the tubes are still good after so many years. If you where to leave it running day in day out they would obviously not have survived that long. Some people think of tubes as lightbulbs that need to be replaced on a regular basis, but you are right, they can actually last for a very long time.