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Yamaha PC2002M Observations

Today´s measurements:
DC board
+/-80V ok.
Idling current
CT~PE
Left :11mV
Right:11mV
DC offset
CT~E
Left:5.2mV
Right:-2.2mV ??
Is this ok?
Last question, what are the specs for the vu meter lamps?
 
Dead on.

http://www.audiokarma.org/forums/showpost.php?p=4242014&postcount=16.
attachment.php
 
Yes now it is :yippy:
and it sounds superb. Had to use CRC electro cleaner on the small trimpots, they were all dry and rough to adjust. Cleaned right level pot too with a q-tip soaked with cleaner. Didnt dissasembly it completely but the result is very good. Have to take the left one later on and I need new lights for the VU meters.
A quick tip: retighten the screws on the main caps, seems they come loose.
 
Those meter lights are plain old leaded 4mm Stanley bulbs that come out of the rubber boots. AK'er dgwojo sells them. Get a grip of green colored condoms to go on them and it will look so much nicer.
 
So how's everyone's PC2002M's running these days? Any additional problems or smooth sailing?
 
mech986 said:
So how's everyone's PC2002M's running these days? Any additional problems or smooth sailing?
Click to expand...

Three PC2002M, One PC5002M (fully recapped), one PC4002M here all trucking along nicely. :banana:

One PC5002M parts - long term fix project...
 
I'm down to just a single PC2002M that I've owned 9 years. It came from a studio in Detroit where I presume it saw regular use. It sees daily use here and except for a re-lamp job when I got it, it's needed absolutely nothing. It runs cool and comes out of protection within about 5 secs.

It stood up to a good AD/DC session with me and the wife last night - gotta love power!

jblnut
 
cdfac said:
how are you liking the PC5002M, btw?
Click to expand...

Technically, it's still on the bench.

It will go onto the 250Ti's this weekend. Been a long time coming I just never seem to find the time to finish it up. Was still chasing that driver board problem on and off.

Just finishing up some cosmetic changes - pulled a few parts from the donor that don't have corrosion on them, deep cleaning, and replaced the lamps with some that are setup a little different and won't melt the plastic.
 
Anybody know what happened to the PC5002M that was sold recently for under $200, wasn't operational and had some cosmetic damage like it was hit on top front. Sold out of Michigan, where at least one other was also sold not working, maybe two different sellers?
 
mech986 said:
Anybody know what happened to the PC5002M that was sold recently for under $200, wasn't operational and had some cosmetic damage like it was hit on top front. Sold out of Michigan, where at least one other was also sold not working, maybe two different sellers?
Click to expand...

No, but I'd like to find another driver card for mine... :scratch2:
 
FYI looks like WDW used them as well. Wish I had the A channel PCB assy as mine is missing it. Is it the same PCB/heatsink as the P2200?
pc2002.jpg
 
IsakAlexande said:
I have had my pc2002m sitting around collecting dust for a long time now. Tried it last july and right channel are -10dB compared to left and have a weak sound. When "pushed" a bit it sounded like the sound were coming trough but I didnt want to fry my ribbon tweet´s so powered it down and put it in storage. As I recall the +/- 80V were spot on but the bias moved up and down. Could it be the TL072 and 2SK146 messing up?
Click to expand...

I know this is in reply to an ancient post but I must share my troubleshooting tale since it might help you.

After deciding to find another PC2002M to get my basket case unit going I resoldered every joint on the DA and PDA boards (Ch1) only to have extremely low gain and distorted output if I cranked it. The output transistors were all new and the other channel worked flawlessly with enough power to bring my test speakers to their knees. The problem sounded EXACTLY as you describe.

What was the culprit? It was the bias protection circuit. Specifically the 2sc2320/2sa999 transistors were extremely leaky but not quite shorted. The three 390 ohm fusistors were also bad (replace them with 1/4 carbon film according to AK Yammie-master Avionic). Just for good measure I also replaced the 1uf 50v cap in the same circuit but it was definitely the fusistors/transistors on my unit.

I suspect there may be a way to disable the bias protection circuit but given the insanely low cost of the two transistors ($1 American) it would be silly to do so.

Just as an aside, while its really great to hit up AK and find somebody who fixed the same model with the same symptoms as the one you own, that doesn't mean you should blindly shotgun various fixes without any evidence. When you start using you noggin to fix gear then you can help others fix theirs and that's what makes AK such a great place.
 
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