Klh r5100 turns on then shuts off

[hpaca509]

Greetings to all i have a klh receiver that when i push the power button it turns on but shuts off. I hear the first click and the second click turns off. I took these pics of the boards. Its raining here in seattle and lighting was an issue. When i disconnect the colored ribbon the receiver stays on. The ribbon is the one in the pic. So i have figured that much out. My tools that i have are limited to a craftsman multimeter and a soldering iron. I would like to fix this and am up to the challenge if someone would guide me through this. I have successfully fixed and hp pavilion monitor, samsung plasma, and zenith plasma through your help and patience.

[hpaca509]

Here is a clear picture of board sorry.

[Toasty]

By the pics, you have the signal cable and the power supply lines to the amp disconnected. What happens if you just have the power supply disconnected? Vice-versa?

Sounds like protection is interrupting the amp supply to prevent damage to the speakers. Check those output transistors for shorting or leaky and the drivers before them. The driver transistors are probably the (10 or 20) taller, half-round transistors just in front of the (10) output transistors. A bit of a side shot would help on relative sizes.

The white blocks are 5 watt power resistors at 22Ω. There are also power resistors at the feet of the outputs. Check all of those those for open or too high ohms.

A schematic would help us troubleshoot.

Toast

[Jon B]

Hi, I believe the white 5 watt emitter resistors are .22 ohms. Common values for those would be .1 .22 .33 .47 and would be marked accordingly.

Toasty is correct, it sounds like it is going into "protect" follow his advice and check all the output and driver transistors along with the emitter resistors.

Also check the power supply voltages with the cable on and off to see if they are balanced.

How many different speaker outputs are there? It looks like there should be 5.
Good luck

Jon B

[kc8adu]

.22 would be what i would expect too.
in the pic look at the one above the datecode.is it cracked or is that a hair on it?
check all those power transistors for shorts/leakage.

[Toasty]

Yeah, the markings throw me off sometimes. The R takes the place of the decimal point.

R22 = 0.22Ω
2R2 = 2.2Ω
22R = 22Ω

A decent resistor marking guide: http://www.diyaudioandvideo.com/Electronics/Color/

Toast

[mxslick]

Toasty,

Thanks for that link, very handy indeed!!

[hpaca509]

Hello everyone I came home from vacation and went to work the next day. When today I went downstairs to work on this thing and my wife chucked it in the garbage. So I guess I will no longer need help. Thanks:bas h:

[romansroad]

OUCH!

[cadiman]

I hope my wife isn`t reading this!