Toasted 400 still toast

roccus

Chief Journeyman
Joined
Jul 4, 2016
Messages
1,112
Location
Maine
Tagline
You'll blow your ears out kid
So Joe what's up?? We were in the middle of diagnosing here you said we were zeroing in on the problem then you disappeared. Whats up with that? Are we going to get this thing fixed or not?
 

roccus

Chief Journeyman
Joined
Jul 4, 2016
Messages
1,112
Location
Maine
Tagline
You'll blow your ears out kid
It's sunday and Joe is also a working stiff...... Relax
Perry get off my ass, if you have nothing to contribute to get my amp running then stay out of this... I see you don't like people butting into your business well neither do I
 

WOPL Sniffer

Veteran and General Yakker
Joined
Aug 10, 2015
Messages
11,223
Location
Minnie-Soda
Tagline
Screw it
No problem. If you happen to see me Taking advantage of people and having unrealistic expectations of expecting help 24/7, you let me know because that would be rude of me wouldn't it?. Sorry
 

roccus

Chief Journeyman
Joined
Jul 4, 2016
Messages
1,112
Location
Maine
Tagline
You'll blow your ears out kid
Perry you run around here flapping your gums at people, paying customers you put us down if we don't have the money to do something your way you trash us for questioning things we don't understand and you seem to like to put your nose in things that don't concern you. "Yer expecting to be waited on hand and foot." REALLLY?? You don't have a clue what you are talking about well I will lay it out for you in public....
Joe and I were going through my amp yesterday he was asking me to check this and check that which I was complying with to the best of my ability. The last thing he sent to me was to ask if I had 0 volts on pin 2, I posted yes 0 volts. Then I got to thinking this was ridicules getting an instruction from him then waiting and keep refreshing the page to see if he had replied. So right after I did the last post back to him I sent him an email asking him if he thought it woud be better to do some of this over the phone and if so if maybe he could send me a time best for him to call today. I then came back to this forum and sent him a PM saying I sent him an email. I sat here for an hour waiting to hear back from him one way or the other... in case you don't know it on the front page of this forum is a list of who is online, all you need to do is put your pointer over the name and it will tell you where that person is in the forum. I saw Joe looking at this tread that thread moving around the forum for near an hour after my last reply to him here on this forum as well as the time I emailed and PMed him. "Yer expecting to be waited on hand and foot." REALLY ass hole something you don't know anything about called common courtesy, would it have been that hard for Joe to message or email me to tell me he was done helping me for the night and that he had plans for today??? Instead of letting me sit here all that time waiting for the next instruction. " Yer expecting to be waited on hand and foot." you know something Joe is the cause this amp blew up he gave me wrong info I did exactly as he instructed. I then tried to work with him or anyone else who could help but everyone here turned and looked the other way the only person who stepped up to help was Dennis he offers up some parts needed. But it still cost me over $100 out of my pocket to get the amp back to where it is now. This all could have been avoided if Joe had done the right thing back then and offered to repair it for free or at least offer up parts but he did not. In fact he is still bleeding me for money, I just sent him the control board to check out and need sill pads for the output transistors... you guessed it he charged me for them. "Time is money " don't feed me this shit I got more time and money into this 400 than you ever put into a 400 as a result of something not my fault. So yea I put the amp aside for a couple years yes I was a bit pissed and yes still am a bit upset. So don't feed me your bull I have put up with a lot of crap over this amp shit that should never have happened, or ever happen to a WOPL customer. But somehow you feel you have to be Joe's little pompom boy and stick up for him. So why don't you just stick to sniffing your own wopls and get the fuck off my ass.
 

Gepetto

Administrator
Staff member
Joined
May 15, 2011
Messages
13,475
Location
Sterling, MA
Tagline
Old 'Arn Enthusiast
Hi Ray
The offer I made to you on January 24th still stands where I offered to get your chassis running if you ship it to me. At this point, we have no idea what is wrong with it and why it has this apparent line voltage sensitivity.
 

orange

Veteran and General Yakker
Joined
Jul 6, 2010
Messages
17,704
Tagline
Broken beyond repair but highly affable
Perry, Ray has been through a lot with this. He's understandably nervous. Let Joe help him out.
 

Gepetto

Administrator
Staff member
Joined
May 15, 2011
Messages
13,475
Location
Sterling, MA
Tagline
Old 'Arn Enthusiast
Next lead to run down Ray. This is going to have to be done extremely carefully as the accessibility is limited. Attach you DVM negative lead to the B- test point on the backplane board, TP6. This is your -80V supply. With your positive DVM lead, very carefully probe the voltage on R17R, R18R and R19R where they attach to the emitters of Q3R, Q4R and Q5R respectively. You will likely need to do this from the backside of the control board as the TO-92 heatsinks are in the way on the topside of the board. That is why you need to get it set up in a way to ensure that accidental shorts do not occur.

Each of these 3 readings should be ~0.27V and they should be very close in value to each other.

Since your offset is in the positive direction and is voltage sensitive, we are testing this path to ensure that each of transistors Q3-Q5R are functioning and sharing equally. If one or more is bad you will have inconsistency in the measured voltage on the 3 resistors and the amp will not have enough gain to properly center the offset voltage.

This measurement should be taken with your variac turned to 120V and the amp sitting at idle. Be very careful with your setup. We do not want this to cascade into a bigger problem. If you have any questions before performing this, please ask.
 

roccus

Chief Journeyman
Joined
Jul 4, 2016
Messages
1,112
Location
Maine
Tagline
You'll blow your ears out kid
Hey Joe I know it's getting late so will not be able to do much just got home a short while ago spent most the day at t the hospital with my wife...

Anyway yea I was going over the schematic last night thinking the problem has to be in voltage regulation I see where you had me lift D9 and 10 that takes some of the circuit out of the scene, and it was looking to me like Q3,4, and 5 must be where voltage gets regulated where the power comes into the right channel.... I will go ahead now and check it out
 

roccus

Chief Journeyman
Joined
Jul 4, 2016
Messages
1,112
Location
Maine
Tagline
You'll blow your ears out kid
Q3 +.3771
Q4 +.3764
Q5 +.2750

So is this telling me Q3 and Q4 are bad???
 

Gepetto

Administrator
Staff member
Joined
May 15, 2011
Messages
13,475
Location
Sterling, MA
Tagline
Old 'Arn Enthusiast
I would also ohm out the 3 - 133 ohm resistors R17-19R that are associated with these resistors to ensure they are still 133 ohms.
 

roccus

Chief Journeyman
Joined
Jul 4, 2016
Messages
1,112
Location
Maine
Tagline
You'll blow your ears out kid
No Joe I did not replace any of those... I never saw a problem till I took the DBT out which then gave full 120V voltage...
I did check the resistors in circuit, all 3 on the left side come in at 132ohm, on the right side Q5 is 132 and Q3 and Q4 come in at 133ohm
 

roccus

Chief Journeyman
Joined
Jul 4, 2016
Messages
1,112
Location
Maine
Tagline
You'll blow your ears out kid
I stopped by hardware store yesterday got some new nuts without star washers, they are a bit smaller but same thread so should be good
Q3.JPG
 
Top