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Jerry Moriah

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Just pulled the CRT, can someone tell me what the 2 heavily insulated and braided wires with round connectors to the rust colored connector on the CRT are? Are they from the CRT controller? Looking to check voltage from CPS, I assume it is one of the wires on the other connector. Looks like red/grey for power, and black/yellow, and black/purple for ground?

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That was key on, with the engine running at the CRT plug I have:

Red/grey          14.2V

purple/green   12.4V

blue/orange     5.4V

black/purple    2.9V

black/yellow    2.4V

black/green    2.9V

brown/red       5V

 

The wiring diagrams I have are difficult to read, but looks like black/purple and black/yellow are supposed to be a filtered/clean ground? Anyone have any thoughts on these readings??? Does it look like my CPS is working and should be supplying the correct voltages to my IPC also? IPC is connected, the CRT removed.

Edited by Jerry Moriah (see edit history)
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Pulled panels off under steering column and I can see some of the ICP wires know, I am afraid to try and remove the connectors from dash due to possibly breaking the brittle plastic. Getting dark out so I will see if I can get some readings at the IPC connectors tomorrow? Is there a secret to slipping the IPC connectors free?

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The IPC connections stay in place in the dash. Just remove the 4 screws and grab it on either side and pull. The IPC slides out and then to replace it slides back in, almost like it has grooves. 

 Regarding all your electrical questions you will probably have to wait on Kdirk. He will know.

 I'm just a "swapper". I trust the wires and connections are good and I swap componants with known good components until the issue is resolved. Don't even use the service manual anymore.

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Thanks for the input,  I have had the IPC in and out probably 10 plus times know,  getting pretty slick at it! I believe the CPS is just to the right of the brake pedal? Was mostly trying to see if I could identify IPC wire colors looking up beside the steering column. Not gonna be easy on an old neck!

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FYI, the dual coaxial cable with the rust colored plug is the video signal and vertical sync signal from the CRT controller to the CRT. Don't measure voltage on that connector, as both signals are very low level AC and there is nothing to be gained from measuring it. Could also potentially damage the RAMDAC chip in the video output circuit of the CRT controller.

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So,  Kirk,  any input on why I would get voltage on the blk/purple, and black /yellow when my diagram says they are clean/filtered ground from the CPS? what is a clean/filtered ground? I asked an ET at work,  he said defiantly not the coffee at QT!

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Just popped top on CRT,  quite a bit of corrosion dust fell onto board under cathode tube, there is a large 4 contact device with brown W shaped heatsink, I think? It was covered in rust dust,  I'm sure it was shorting out.  Red gue all over the board under cathode tube,  guessing from green capacitor under tube? Tried to do a quick dust wash,  gonna blow dry it to evaporate any solvent and warm it up and see if I can set my heat! Wish me luck!

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So put her in hot,  no joy,  put blow dryer on CPS and the CRT came on after a short while! Took blow dryer away from CPS and the CRT went off. So can A good CPS be bought? And it has one of those connectors from hell! Pushed up tight to brake switch wiring... Just hoping for heat the next couple mornings,  cranked her to 80!

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Yea, some of my posts from my phone dont show up. My CRT stayed on all the way home today, heat set to 80, kick panel removed so I am guessing it is the heat on the CPS? But maybe the 5 minute carb cleaner and compressed air cleanup helped :P:D Normally as cold as it was, and no sunshine, it wouldnt have come on at all.

 

Edited by Jerry Moriah (see edit history)
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The first thing my CRT says is that there is an electrical issue, then  low anti-lock brake pressure. If I knew how to use the diagnostics, would it have pinned down the CPS issue? I think I tried once, but that was a while ago, wasn't driving her much then.

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Ok guys , when you are testing voltage , whether with a DVM , or the hated test light , you need to remember that not only does electricity flow out from your battery , but for the component to work the electricity has to flow back to the battery. That is why everything is grounded.  The flow through whatever component is what makes it operate, and the AMPS are how much of the available electricity is consumed.   So when you test for voltage on a ground wire there is a very good chance that your tool is completeing the ground circuit and that is why you get a reading.

    The good side of understanding that is that you can use that same theory to test the ground side of your circuit. Say your headlamp is dim , but when you check you have battery voltage there.  Put you test light from a known good ground to the ground post on the headlight. If your test light glows , you know that you have resistance on the ground side and can work from there.  Electricity always takes the easy route , and if your light has an easier path to ground that the ground wire it will flow through your test light.

Edited by SteveT
misspelled (see edit history)
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So,  Was really hot in car, so CRT worked all the way home,  replaced CPS,  with door open of course,  so car cooled down some.  With new CPS,  NO JOY <_< old CPS back in still CRT doesn't come on,  so either something else close to CPS  is affected by the blow dryer blowing heat up in that area,  or the Heat I applied to the CRT took some time to affect it's function?  When I started blowing heat on CPS, CRT finally came on from heating it before hooking it up , then when I stopped blowing heat on CPS the inner workings of the CRT cooled off at the same time making it appear the CPS was responsible? I suppose I would need to pull CRT from hot car when it is working,  cool it off,  plug it back in and see if it works before it warms up?  So where is the CRT controller?

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