Accuphase E-202 No Sound

[fdeelros]

Hello everyone,

Hope y’all had a great holiday weekend. So, I started an Accuphase E-202 thread sometime late last year and I was getting help from many of the gurus here at AK. Unfortunately I got sick and had to place many of my projects in standby to focus on my health.

I was trying to get the amp shipped to Echowars for a pampering restoration, but unfortunately he has been unavailable for quite some time and probably will be for a little longer (very busy man) J. Per his advice, I ordered the caps, transistors and variable resistors (for bias and dc offset) and decided to tackle the project myself over the past weekend.

I changed all the caps in the PS board (719-0004-00) and also, per Glen’s advice I replaced three- 2sc1451 from that board. From the driver boards (710-0002-00) I replaced a couple of capacitors (c8, C3) and one 2sc1451 from each board (I think it was Q3 just below VR1) and replaced the adjusting pots. I also purchased the big filter caps and I plan to replace them over the weekend.

So the amp powers up and the relays clicks immediately, however the amp produces no sound. I checked the back and it has a switch (normal/separate) which I think is to use the amp as preamp if desired, it is switched to normal.

I tried moving the switch and connected some RCA and still no sound. By the way, feeding the amp with an iPod thru AUX1/AUX2. in the process of elimination I check the temp on the OTs (2sc679 & 2sc1079) and two get really warm and the other two barely warm up.

I suspect that the two with the lesser temp may be bad. I will check the schematic this afternoon and verify the voltages coming out of the 4 TO. Question: In the event that the 2 in question are fried, what are the best replacements? Also, if the TOs require replacement, should the pre-driver (Q7, Q8, Q4) be replaced as well on each board?

Lastly, when I turn the amp on the relay engages immediately and it takes about 30 seconds before it disengages. I was reading an old thread here at AK where someone found an NPN posing as a PNP in the PS/ protection board- He said that he corrected them and the problem went away.

However, he did not specified which transistors were reversed. I dont think is any of the 1451s as they were replaced. I apologize for the long write, but I wanted to be as thorough as possible as I really want this amp up and running. I only hear great things about it and want to experience it. Thank you in advance for any help you guys can offer.

PS- I purchased the amp as is for a reasonable price- there was no sound before the recapping either, only the promised that it porwered on*

Felix

 

[unfairlane]

Hmm, must (try to) think..

 

[slimecity]

I tried moving the switch and connected some RCA and still no sound.

So - you ran a cable from the "pre out" RCA's to another power amp and still no sound?

Or; you ran a signal source into the "main in" RCA sockets and got no sound?

My feeling is that the problem will either be in the pre or power section, you will be unlucky (but its possible) that there will be a problem with both sections.

 

[GrzegorzW]

Hello Felix

Did you solved problem? I know post is 8 months old, but I´m really courius, what was wrong. My friend is about to buy same model, with the same fail for reasonable price.
Is it worth to play with it? In my case (have bought Accuphase E203 really cheap) the problem is bad caps, main is working almost good, when connected to external pre( occasionaly distortion from leaking caps), pre is working with one channel with small distortion(hum), sec. channel almost not working - only loud distorted signal from the speaker. Btw. have you measured speaker relay´s contacts, when activated? Difference in ammount of heat dissipated from output transistors means at bias current have to be adjusted, according service manual.

Best regards
Grzegorz

 

[nj pheonix]

It's not clear to me.
Was the unit working when you started?
As a rule I like to do a section, then test.
If you run into a problem, you know what section has the issue.
I don't know you're skill level, it's possible you have more than one issue?
One other off the cuff guess (possibility)
Sometimes replacement transistors have different lead orientation to their physical appearance compared to originals.
Was this checked prior to installation?

 

[blhagstrom]

3 years later...

Is this the amp you sent to me?