1969 TOTL 140X

M0therG00se

Active Member
I acquired a Kenny today and it has always been calling my name since I picked it up and felt how beast it was many months ago. I guess from the information I'm gathering is it's DC offset is the reason it could boil an egg on top. I'm not going to run it like that so luckily it's equipped with pre outs and main ins. The tuner is amazing sporting 4IC and 3 Fet I believe correct me if I got that backwards...

The only issue besides it getting super hot is the crack in the tuner station numbers. Here's a few pictures of my "entertainment" part of my room. I put it all together today and I'm quite proud of the "strictly music" corner and across from that this area I put together today. Anyways I need to fix this offset and I don't believe I should attempt that unless I'm totally educated,...would it be better to have a Tech do it. It would be worth the cash no doubt but I'm eager when it comes to making, fixing, or learning which at my age is a double edge sword.
 

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Don't know if you are going to have DC offset on that amp because it is cap coupled and the DC would be blocked by the caps on the output. (75V/2000µF one for each channel). Caps could be bad allowing DC but that would be very bad for the speakers as it appears to be 42V blocked by the caps. But, I'm only an hour and half ahead of where you say you are in learning this stuff.

What is causing the heat, I got no idea. Maybe someone can drop in and look at the schematic on HFE and make recommendations.

Kenwood always made great tuners and included them in their receivers.
 
Don't know if you are going to have DC offset on that amp because it is cap coupled and the DC would be blocked by the caps on the output. (75V/2000µF one for each channel). Caps could be bad allowing DC but that would be very bad for the speakers as it appears to be 42V blocked by the caps. But, I'm only an hour and half ahead of where you say you are in learning this stuff.

What is causing the heat, I got no idea. Maybe someone can drop in and look at the schematic on HFE and make recommendations.

Kenwood always made great tuners and included them in their receivers.


What do you mean my good man? You are an hour and a half ahead of where I'm at...as in time or around Akron, Ohio? And I hope your right in a way because I have tested the outputs and they all came back good. I've heard these run hot but I'm not sure it's supposed to be this hot. I got a fan or two if nothing's wrong but I'd still feel it needed to circulate air.

I wish I had friends around here that could get down to this bottom of this besides the store guys I know that would want payed. My buddy and I help another out where we can but it seems hard to come by us audio minds here locally.
 
You are learning this stuff and so am I. I was able to see that this unit is cap coupled, indicating I am an hour and a half ahead of you in the learning. If I miss just one class and don't do the homework, you will be where I am as far as working on these things. Parts replacement not much electronic diagnostics or reenginnering.
 
It should not run super hot. You have an incorrect bias setting. The unit can bias super high creating this problem and baking other components .
There are 3 trim pots on the main amp board per channel.
To do a preliminary bias adjustment- use a DBT and a DMM for each channel. Know which trim pot you need to adjust. power on and adjust to about 10- 15mv each channel.(mine were 50 & 350mv prior to restore)
Now the unit heat-sink should be around 45 degrees Celsius when driven hard.
unfortunately your unit is probably showing signs of heat stress to many components.

there is no dc offset -it is cap coupled.
 
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