MVP-861 display out after cleaning laser and belt change.

[Mack]

Becoming a member surely has its perks.

[macman007]

Originally Posted by Cohibaman

You need to become a subscriber to PM. Well worth the entrance fee!

On my list!

[macman007]

UPDATE:

I reflowed a number of solder joints that looked iffy, including the ones mentioned above. In some places I removed that lead-free crap with the desolder station, including connector for J-1 to J-8. I removed Q18 and tested it with my Atlas transistor checker, it reads as a single junction diode. That's no good. When testing the other way there no reading is displayed for Emitter to Base. A multimeter in diode test reads open with leads in either polarity on Emitter to Base.

AS I said before, I don't think I have a substitute handy, but I'll check the transistor crossover to and then see if any are here in stock.

Don't know if it's progress, but it sure seems like Q18 is going to be the key, as long as nothing elsewhere killed it.

EDIT: Nope, nothing here I can use. Maybe I'll order a few from Mouser as well as the caps to do the power supply in my MS-750..

I tried the transistor part number on Audio Classics search page, no results. Not surprising for an off the shelf PNP transistor.

[Beowulf62]

Definitely progress...they are cheap so definitely order a few just in case.

[Formerly YB-2]

Originally Posted by macman007

EDIT: Nope, nothing here I can use. Maybe I'll order a few from Mouser as well as the caps to do the power supply in my MS-750..

If you are going to recap the PS in your MS-750 you might as well do the one in your MVP-861, while you are in there. Great piece........ I probably owned mine for more years (10?) than any other piece of gear that's gone thru my system(s).

[piolaxo]

Originally Posted by macman007

Alrighty,...again once more

Voltage Regulators U14, 15, 16, 17 all test correctly.

Q18 (transistor) 32vdc regulator, I read 38vdc the collector, 32.4vdc on the base, and nearly nothing on the emitter.

Diodes 2, 3, 4 and 5 all test good. D3 / R133 junction should read 23vdc but there is nothing there.

The path between the emitter and J-5 is good, 0 ohms, no open ckt.

Now, why don't have anything on the emitter? I could pull Q18 and check it, but rather know for sure before pulling the bottom off as well.

Either way I don't have that transistor in stock so to speak, so I'd be ordering it and I'd rather make sure I order everything I need at once instead of willy-nilly.

Sorry Cohibaman regarding the previous post ,.. I meant to delete it and not post it, but this one instead

So all the outputs of the U14 to U17 regulators look good? If so, and you
don't have -32V at J1:12, then could you check D4 at both the anode
and cathode? This diode is before the D3 diode that you mentioned.
By checking D4, you are also kind of checking D5. That small supply
doesn't have much, so it's either D4, D5, also D2 and potentially Q18
the potential culprits.

And just curious, could you check the resistors R103 and R104. They
should be low at 5.6 ohms.

Sal

[Beowulf62]

Any progress on your troubleshooting/repair?