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BM4400 Restoration

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dahiyas
Top 500 Contributor
United States
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dahiyas posted on Tue, Aug 10 2021 2:43 AM

Hello once again, this time with a BM4400.

When I got it, there was no POWER ON light, when a source was selected the OVERLOAD lamp flashed briefly and that's it.

Tested and replaced three blown TIP146's and idle current trimmers. Switched on and all was well. Recap was also completed.

Couple of issues still need attention -

1. The Tuning Indicator light does not come ON after the recap. I remember it being one before the recap. I have checked polarity of all the capacitors and everything seems to be fine.

2. When playing FM source the stereo light comes on intermittently. Similarly only the Right Balance Indicator light comes on but the Left one is very dimly lit (initially I thought the bulb was bad), but looking at the bulb from the inside showed that it was dimly lit. Again, this is intermittent. There are times the light comes on but most of the times its off (for the same station). I replaced all the bulbs in any case (Thanks Martin)

3. Whenever I change the source, there is a loud PLOP sound from the left speaker. Right one is fine. The PLOP happens only when changing source. Does not happen when selecting Mono, Loudness. Speakers or Headphones - I can hear the PLOP.

4. AFC switch - Selecting AFC puts the system in Mute. I can still hear the sound but its very very low. Tuning does not have any impact.

I am very tempted to dismantle the front plate but past comments regarding it being a tedious process is making me think twice Sad.

Other than the above 4 issues, the system sounds good.

Any help with resolving above will be appreciated.

Thanks !!

 

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dahiyas
Top 500 Contributor
United States
145 Posts
OFFLINE
Bronze Member

Any hints/guidance on any of the above issues.

 

Thanks !!

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