Kenwood KR-5340 amp

[Woody Rod]

Hello,

I have just come into the possession of an interesting amplifier. As the heading suggests, it is a Kenwood KR-5340 "Two-Four Amplifier". It has 4 channel discrete in/out, which is interesting.

Anyway, on to the problem:

The unit powers up fine and produces sound from one channel...this may require some explanation:

The amp output stages are in modules, two matching pairs to make 4 channels. I have added photos for people that have not seen the inside of one of these amps.

The letters in the photos correspond to the foloowing:

A = Empty slot where the defective amp module was removed
B = Good amp module in place (while playing in this photo)
C = Defective side of removed amp module

What I have done so far:

1. Unit would power up, then cutout relay would go open circuit
2. Checked the relay operated by applying external voltage = OK
3. Removed both amp modules to see if the problem was isolated in one of these, and consequently found that one unit was getting very hot - the one marked "C"
4. Replaced the possibly good unit and obtained sound through right channel only...consequently, the rails are left and right channel respectively, rather than left and right channel on each board
5. Tested known good module in both slots, and later by adding input to both channels, and by changing input and outputs to match the slot. All slots on the main board check OK
6. Suspecting one side of the amp module "C" is the culprit, as this is the only part getting hot, all others are luke warm only at normal listening levels
7. Have resoldered all the suspect side. Have removed the big cap in the centre and cleaned the contact (or whatever it is) from the cap and board - thanks to the info I have read from this forum . Have checked as many of the caps as possible with LCR meter, but can not check for ESR. Voltage seems ok on the faulty board

Ok, so how do I go through a process to find the problem? I do not have a circuit diagram, and can find little info on this amplifier, hence my posting this problem in this forum.

With only one side operating, this amp really has some grunt. Much more than my supposedly 100W per channel Pioneer amp.

Where do I start? I have heaps of caps and resistors etc if I need to change things...and what is a good replacement for the Sanyo D315E / D transistors if I need to replace them.

Thanks,

[EchoWars]

http://www.agtannenbaum.com/k_cat.html#KENWOOD

They sell a manual. Until you have one, you're just ****in' into the wind.

These guys have one too...

[Woody Rod]

Thanks for the directions. I have asked about the schematics being emailed rather than posted...nice to have them this year rather than next year

ANyway, I have a bit of follow up:

1. I have removed the output transistor packs from the board (one at a time), the board still trips the relay with no load and no output transistors.
2. I have removed and replaced the capacitors on the suspect board with known good units.
3. have removed and checked the three diodes on the board

There is no difference so far, as the unit still trips the the relay.

I will try and get a schematic and let you know how I get on.

[phemenwa]

For a replacement for the Sanyo Transistor take a look a 2SD315, it a TO-66 Case.