Wadia x64.4 sledgehammer output stage problem

[RobertS61]

These you mean?:
https://www.diyaudio.com/forums/atta...1&d=1599996176

HA5002:
https://www.diyaudio.com/forums/atta...1&d=1599996663

and the other two not pointed to.

[diyiggy]

Are rhe little yellow caps at the top of the pictures some decoupling wet tantal ? Shorts?

Or manufacturing problem if a common issue whatever the design...I m thinking about cold joints...?!
Are the red units on both boards some relays that need checking as well?

[RobertS61]

To be honest I've no idea.

Those yellow/brown look like tantals (I have no schematic) and those red like indeed like relays that would be worth investing.

My primary question was if I could swap out the boards from the non-sledgehammer outputs with the sledgehammer output boards of my newer working DAC after I made sure all the voltages are alright, connectors etc...
If I swap those outputboards and the unit is working, I know that the right outputboard is the culprit that causes no output in that channel.

[RobertS61]

Originally Posted by madskaman

I was actually able to fix this board after a while. Ended up being the opamp on one channel after all that. Ha5002 I believe.

Wher did you source that metal can round opamp?
Seems obsolete..
Only available on Ebay

[madskaman]

Correct. The painted black cans are opamps. I replaced the bad one with HA2-5002. And yes, had to roll the dice on eBay.

[RobertS61]

Okay, clear.
I will investigate first if it is the outputboard and then I will try to investigate further.
How did you find the faulty one?

[madskaman]

I would probably just unsolder the opamps on the bad channel and swap them. If it is a bad opamp, then you would have a similar symptom with xlr (low gain) but your rca would output correctly.

You could check voltages and signal before... but if it's playing from the xlr, then voltages are likely good. You could check to see if you have signal at the input to the opamp. I checked mine with a dmm, ac voltage at pin 8. I had something like .6v with it "playing" and nothing on the output. If you have no signal on the input, then that would point to a relay upstream preventing signal to pass through.

[RobertS61]

The XLR plays at a low volume indeed.

So just swap the two HA2-5002 opamps in my faulty channel you advise?

All the DC voltages are okay.

[RobertS61]

These is the Wadia 2000 year 1990 version outputboard:
Leftchannel working:
https://www.diyaudio.com/forums/atta...1&d=1600179335

Rightchannel dead on RCA low level on XLR:
https://www.diyaudio.com/forums/atta...1&d=1600179341

Soldersite of the Left- and Rightchannel:
https://www.diyaudio.com/forums/atta...1&d=1600179341

With a black marker a OK with date and paragraph is written on this site at 1-9-90 being probably an American dateformat meaning the January 9 1990.

It's a bit tricky to get this board out.
There's almost no grip on the RCA nuts at the back and the 6 hexscrews are tightened with 100 lbs torque so I needed to extent the key to get them loose. One slip and you're done...

I think I lack to proper soldering skills to get these HA2-5002 opamps desoldered so I let a more experienced friend of mine desolder them.
I ordered 4 in Hong Kong and hope at least two are good...

[analog_sa]

These, being diamond buffers with no voltage gain should be easy enough to troubleshoot even without a scope. Just take them out and jumper IN to OUT.

It may even sound better that way.