Deiimos
CarAudio.com Veteran
Make its text the same color as the forum background.
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Not even sure if that would work lolMake its text the same color as the forum background.
Deiimos
CarAudio.com Veteran
Well that does help at least, now you know the ground, 12v+ and ACC wire, so you can power the stereo on.
I was typing a response telling how to use that big diode and inductor / ohm meter to find the 12v wire, but being printed on the board makes no need for that. At any rate, once you get it powered on, a volt meter will be handy to find the power antenna and remote turn on wires (12v output when stereo / radio on), and then can carefully try to test for AC output for speaker wires playing a music / test tone if available. Or find the chip-amp IC and see if you can find its part number to see its pin-out, then follow the speaker outputs to the correct pins, it's already pretty far disassembled.
- Thread Starter
- #20
Well I couldn't find my multimeter, so I made a test light and this is what I found out...
So there are 11 grounds... and If I connect one wire from the light to the "BATT-" labeled solder point on the board and connect the other to one of the pins I marked with a blue minus which are the grounds, something clicks on the board, and the bulb lights up slowly...
And If I connect one wire to the "BATT+" and the other wire to the "BATT-" the light turns on so I guess there is a short somewhere...
Deiimos
CarAudio.com Veteran
It could have a blown amp-IC chip too. Looks like someone installed a “bodge” “track repair” wire at some point as well (the yellowish wire on the solder side of the main board).
It may still partially work, so won’t know until you try.
I had an old 90’s Pioneer head unit back in the day with a blown chip-amp IC so it had no output to the speakers, I removed the bad chip, fixed a couple bad board traces, but the RCA outputs worked fine so it still ran the whole system as I had external amps.
That said, I’m guessing it is a cheaper brand head unit, and like not worth putting much effort into repairing. If it is dead I’d personally stick it in the parts box. If your unit was ever hooked up backwards it may have too much wrong at this point.
It may still partially work, so won’t know until you try.
I had an old 90’s Pioneer head unit back in the day with a blown chip-amp IC so it had no output to the speakers, I removed the bad chip, fixed a couple bad board traces, but the RCA outputs worked fine so it still ran the whole system as I had external amps.
That said, I’m guessing it is a cheaper brand head unit, and like not worth putting much effort into repairing. If it is dead I’d personally stick it in the parts box. If your unit was ever hooked up backwards it may have too much wrong at this point.
Deiimos
CarAudio.com Veteran
But yes, if you were to try to power it up, these are the 3 pins you want as far as I can tell. The 12v+ and ACC both connect to the battery 12v+ terminal for testing purposes, and ground of course to battery negative. This should allow it to fully power on. The other pins being tied to ground may be from a bad output chip, but might not know until you test it, and perhaps the light bulb tester is making the circuit act unusual, not sure.
Deiimos
CarAudio.com Veteran
That could be a difficult problem to sort out.
It's possible it has a micro-switch somewhere to detect when the screen is open and its contacts are dirty or damaged, perhaps a sensor in some cases. Or, maybe even a ribbon cable causing an issue, cracked ribbon, damaged connector, ribbon not seated in its connector well. Reminds me of those old CD-ROM drives where the tray closes as soon as you open it, maybe research those to get an idea as well.
I also had a Pioneer touch screen with a bad ribbon, I think it stopped it from opening correctly and or displaying things, at any rate, the ribbon can cause problems in the motorized screens. The Pioneer was not a flip out screen, but the face was motorized to drop down to put a disc in or SD card or whatever. And actually the ribbon wasn't bad in it if I recall, the connector the ribbon plugged into broke and it didn't have enough pressure to make contact, so had to bodge it a bit to make it make contact again.
Since you had it disassembled, maybe make sure any ribbon cables, especially those going to the screen are seated well and or not damaged or gotten pinched, they can be very fragile and easily damaged, even if they look okay. edit: and they just flat out go bad sometimes from flexing / open and closing it over time.
Could be a bad component causing it it to malfunction, which could make troubleshooting near impossible, really hard to say at this point. Also make sure your small SLA battery is fully charged to be certain the voltage isn't dropping too low causing the head unit to behave weirdly when trying to open its screen. Unlikely, but something to rule out. Perhaps test all the buttons to see if any seems stuck, that can cause wired problems sometimes too.
Other than that you may just have to tinker with it and hope for the best.
It's possible it has a micro-switch somewhere to detect when the screen is open and its contacts are dirty or damaged, perhaps a sensor in some cases. Or, maybe even a ribbon cable causing an issue, cracked ribbon, damaged connector, ribbon not seated in its connector well. Reminds me of those old CD-ROM drives where the tray closes as soon as you open it, maybe research those to get an idea as well.
I also had a Pioneer touch screen with a bad ribbon, I think it stopped it from opening correctly and or displaying things, at any rate, the ribbon can cause problems in the motorized screens. The Pioneer was not a flip out screen, but the face was motorized to drop down to put a disc in or SD card or whatever. And actually the ribbon wasn't bad in it if I recall, the connector the ribbon plugged into broke and it didn't have enough pressure to make contact, so had to bodge it a bit to make it make contact again.
Since you had it disassembled, maybe make sure any ribbon cables, especially those going to the screen are seated well and or not damaged or gotten pinched, they can be very fragile and easily damaged, even if they look okay. edit: and they just flat out go bad sometimes from flexing / open and closing it over time.
Could be a bad component causing it it to malfunction, which could make troubleshooting near impossible, really hard to say at this point. Also make sure your small SLA battery is fully charged to be certain the voltage isn't dropping too low causing the head unit to behave weirdly when trying to open its screen. Unlikely, but something to rule out. Perhaps test all the buttons to see if any seems stuck, that can cause wired problems sometimes too.
Other than that you may just have to tinker with it and hope for the best.
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