|
|
Post by jukenorman on Apr 1, 2023 19:24:57 GMT
Hi Jacob,
It's not clear from your post but you must never rely on the LEDs to prove that the +&- 5V is OK; you must use a meter to confirm it. You could also try loading up these voltage rails a bit, maybe using a 6V lamp (at least initially) to prove that they are stable before condemning the control unit. If you are intending any serious fault finding on these circuits, you really need copies of the large schematics. You can get these at jukebox-world.de (Germany), I don't know about the U.S..
Norman.
|
|
|
|
Post by buttersnip on Apr 1, 2023 21:35:20 GMT
Thanks Norman! Yes, I’m aware the leds are not indicative of actual 5V…but I have also been unable to trace which pins in the molex connector (to Control Unit) are providing +5V, etc. I have tested the voltages there yes, and I don’t like what I see yet, but I’m lacking without more information. The large paper wiring diagram would be a dream! I think in this case, it’s just too expensive to get it to the USA for what it may be worth to me. I agree that this Control Unit may work, I only meant to say that if it was bad, it seems pretty hard to find now. Thanks again! It’s hard to know how to write technical q&a for me, bear with me.
|
|
|
|
Post by jukenorman on Apr 2, 2023 9:46:12 GMT
|
|
|
|
Post by buttersnip on Apr 3, 2023 16:06:23 GMT
This is fantastic Norman! I just tested all of the relevant points in your diagram pic, extremely helpful! You've got that genius! Here are my findings:
02-11 57.5V
02-12 12.0V
02-14 15.3-4V
02-16 -8.4V---(creeps down to around -7.0V)
02-17 1.8-2.0V
02-19 17.2V
My thought here is to try replacing the +5V/-5V VR's again?...I would hate to admit it? but perhaps I embarrassingly cooked them somehow along the way? , and...they are inexpensive. I swore I was done taking these 12 screws out of the mosfets/VRs/BR...Ugh! ha ha! This board is just not the most fun! Just put on fresh goop too!!
I feel like the other numbers should be in range enough for start up?
Thoughts?....
|
|
|
|
Post by buttersnip on Apr 7, 2023 21:17:36 GMT
Picked up my 5 V VR’s, replaced both, lights all came on, but 5V+ went out quickly? (*Without cable to 02 connector) ….Everything looks great? -5V now tests perfect -5V…Nothing else should have changed? I had thought it blew the led from high voltage? But tested fine. Feeling pretty foolish now as this circuit seems too basic to get wrong? Anyone’s further suggestions or ideas are appreciated.
|
|
|
|
Post by jukenorman on Apr 8, 2023 9:17:47 GMT
Hi Jacob, Did you check the diodes in the rectifier bridge? I find the normal failure mode is electrolytic goes short circuit, takes out rectifier diode(s) which goes short which in turn takes out the fuse. You're right though, it's not overly complicated! Is the +15V OK, that would probably rule out the rectifier?  |
|
|
|
Post by buttersnip on Apr 8, 2023 17:25:52 GMT
Thanks again Norman! Yes, I had checked rectifier and Catalytics first from your prior knowledge/replies to similar situation. This one never blew fuses. I’m feeling like I never understood how the VR’s properly sit on heat sink now? They all had paste, only the 15V, and the -5V had little plastic “shields?” As well. I can’t understand if any are supposed to “ground” there?…either way, even with mica washers? You have a metal screw going through it?…I accidentally deleted the first post on this thread, But I’m done with this machine for now, too frustrating to continue. If anyone else learns anything from this thread, take the sage advice given repeatedly: Read any and all service manuals thoroughly first, and… START WITH THE LARGE PAPER WIRING DIAGRAM!!!
|
|
|
|
Post by jukenorman on Apr 11, 2023 7:47:51 GMT
Hi Jacob,
It seems a shame to give up for the sake of an insulation kit (and another voltage regulator, I suppose!).
Norman.
|
|
|
|
Post by buttersnip on Apr 11, 2023 14:29:31 GMT
You are right Norman! And It would be unusual for me to allow myself to not keep trying. I will be giving it 1 more shot, just taking a weeks break!
|
|
|
|
Post by buttersnip on Apr 29, 2023 18:31:22 GMT
Ordered a couple components, then slacked in getting back to this! But today I found that one of the caps near my 5V+ VR actually had a broken, likely barely touching “leg”…This explains a lot!!! It was difficult to see with close surface mounting, and I did not actually find until I pulled it today….once I get a replacement I shall continue.
|
|
