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I bought a Kenwood KR5200 for parts for my 5200 that I have had since 1972. I couldn't help myself and began to clean it up. The speaker sounds strange and "tinny" no bass sounds and weak output, however the head phones sound great with all functions seeming to work well. I plan on continuing the cleaning. Can anyone point me in the right direction on the speakers ?? Thanks
Follow Ups:
The 3 primary causes of your problem (in the poweramp section) are weak output transistors, bad bias circuits and bad electrolytics.The headphones should be amplified by the input drivers of the poweramp.
Strange thing...I cleaned a little more with radiosh*** control clean and lube...just the speaker wire connectors...then quit for two days. Today I attached the speakers. It crackled a bit on powerup and then played Loud and clear. Four hours later..after several manual shut offs and on...it is still running great. I have some deoxit coming..going to clean with it. I am assuming that it was owned by a big smoker, cause the stains were really thick and tough to get off the knobs. Any advice??? I'm a little apprehensive about putting it back together right away. Thanks.
The main culprit in your case is either the speaker output switch (usually says OFF,A,B,) - clean the contacts of this switch really well with de-oxit. It could also be the relay that closes to enable output to the speaker terminals. Some models have it, some don't. You usually hear it go "ping" a second or so after power up if you have it. This is tricky to clean the contacts, you may have to remove the plastic cover to get in there. Do that last, I use a white card with de-oxit. Also, don't know if you have it on that model, but the switch on the back panel that is labeled "PRE-OUT AMP IN" is a weak point on Kenwood amps and should also be cleaned very well. When dirty, it can cause intermittent problems with no sound output.Or, it could simply be corroded speaker terminals as you say.
FYI, there is no such thing weak output transistors. For all practical purposes, they either work, or they are blown. Always check for simple things first before deciding to replace any parts.
Thanks for your reply. There is a plastic covered "switch" (omron) that "clicks" a few seconds after I push the on switch. It seems to click about 2 seconds slower than my kr-5200 I bought over 30 years ago. There are two "rca" plug ins for pre-amp out but no switch. One other thing. This 5200 has the 110v/220v switch on the back and is blocked off so only 110 is available and the power cord plug has round electrodes...came with adapter to fit into State side electrical outlets. Also the two outlets (switched & unswitched) are covered by a factory cover. I suppose someone picked this up on the way back from an overseas assignment. Anyway it is something I got for "parts" for my old faithful...fun to see it run. Thanks again.
The poweramp could also have bad solder joints.
Thanks, I will look into that.
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