VideoKarma Member
Join Date: Dec 2023
Posts: 5
Hi there, I replaced about 60 Capacitors in the tv unit, and around 30 in the diversity unit. All through hole caps.
Today I hooked up my diversity unit to the tv for the first time, I had to figure out the connections for power. There's 2 ground pins, BATTERY, ACC, and REMOTE, all 3 need to receive 12 volts for the unit to power on.
Thankfully the custom cable I made using a old floppy drive ribbon and 26 pin female Centronics connectors was able to handle the current and didn't burn up lol. If you need a cable this is definitely the cheapest and easiest way to do it.
Everything powered up fine, but the screen still shows the same white raster, no menu or anything. When I press the buttons it beeps now so that's a good sign the two units are communicating.
I have 8 of the displays working. Only using 1 of the diversity units for all though.
I have 7 displays consistently working. Only been testing with 1 of my diversity units though.
>>>>this suggests your divirsity unit is not fully repaired. Do you see/hear the relay actuate?
Maybe its not displaying because I haven't hooked up the pins for the "safety harness" that disables the video display when the car is in drive. But I would assume it should still display the menu so you can tune the radio while driving. Ill try that next but I don't know what kind of signal they are expecting.
>>>>>safety harness/connector_jumps is/are not necessary.
I would also really appreciate HelloVoltage's input, tell us everything you know please!
If HelloVoltage hasn't already, I intend to reverse engineer the connection between the diversity unit and the tv to see what video signals are being passed. But I need a fully functional unit first.
>>>>video is ntsc. Not sure if it's the 7(6?) line down version from japan. It's ntsc either way for testing.
Update: Something I forgot to mention is that after the white raster gets "squished" half of it turns grey. I discovered that by adjusting the blanking pot on board B the grey part gets brighter or darker. Board B appears to handle the beam indexing and feeds the amplified video to the neck-board and then the cathode on the CRT.
>>>>> avoid messing with pots.
Nothing happened when I tried feeding the B board a video signal into one of its RGB pins either.
>>>>>Please point out what you thought you were doing on the "b" board. I have so far only been able to partially batch in a composite signal without the divirsity unit. see : (
http://www.videokarma.org/showpost.p...&postcount=178) image 6. Injecting rgb looks to be possible, but not yet successful. Not much attempt though
I also discovered that by disconnecting the photo sensor board from board B, the pin cushion distortion doesn't happen and the white raster fills the whole screen without changing.
>>>>never tried that
I suspected maybe the diversity unit was not sending video so I tested the connector with my oscilloscope to find what looked like a video signal and I came across one that sort of looked like a video signal and it changed slightly when changing from TV to VIDEO/WM.
>>>>do you have photo of your divirsity unit?
Unfortunately while testing I had the tv running for longer than any time before and I heard a small pop|
>>>>ouch
and smelled something I can only describe as "too hot electronics" and capacitor juice. So I shut it off and that's as far as I've gotten. I inspected a little and haven't found anything obviously burnt or damaged yet. Checking with a infrared thermometer nothing I can see seems to be getting unreasonably hot, even the vertical output transistor only gets to around 130F
If only there was a service manual available.
Last edited by dinorhino; 03-20-2024 at 11:10 PM.
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I have no service manual. Just went through slowly cleaning vias, replacing caps, controlling power. Only mistake so far was the assumption about the proprietary composite jack which is also 3.5mm.