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donated HK3370 with interesting issue

Bpscorn

Bpscorn

New Member
SO as people often seem to do, I've been given a HK3370 Receiver to look at/dispose of./ It has the common power on, immediately switch off/protect error so common with these, BUT for one small difference. The mute button prevents the board from going into protect or shorting out. I've issued the standard reset, and tested voltages when plugged in but on standby at outputs and all seems fine until the standby is switched on and *click* gone. Unless I hit mute. Its the mute factor that throws me

This leads me to believe (as a guess) it's possibly one of the transistors that prevents freeflow current going to speaker outs. but I could be very wrong. I'm so-so at soldering, and can DIY fix most problems but this one has me baffled even after looking at the schematics. Unlesss I'm missing some grounding screws somewhere...Could be the MCC I guess but I've also heard the capacitors were underarted for these....

Any thoughts or just sell for spares? Was hoping to use the power side amp but not the pre.
 
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If anyone wants to have a go at fixing it and moving it on themselves I'll part with it for £20 plus postage or local collection.. I paid £40 hoping it was simply blown fuses (I wasn't allowed to inspect the interior prior to purchase). Otherwise its going in tut bin
 
are you saying relay clicks with mute on ? if so i guess dc is getting into the signal before the muting circuit . muting generally shorts the signal to ground .
would be easier to diagnose with a schematic for it .
 
This is the schematic. As soon as you hit standby, loads up and within 1 second clicks out into short/protect unless you hit mute and then hit standby to turn back on

3370 schematic.png
 
petehall347 said:
thats not a schematic .it is a block diagram .
anyway try pulling the jumpers .
Click to expand...
Apologies, I rushed the link. I currently don't have the pre-main jumpers in, we are talking the jumpers that connect the external pre out to main in yes? It doesn't make a difference if I have them in or out the fault remains the same, just like the song :P
 

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petehall347 said:
are you saying relay clicks with mute on ? if so i guess dc is getting into the signal before the muting circuit . muting generally shorts the signal to ground .
would be easier to diagnose with a schematic for it .
Click to expand...

I'm prettu sure this is happening, but I don't know where as schematics are hard for me to read (ie still learning to read them correctly)
 
no worries, I have the full copies but Can't upload them all and it would just be a pain. the main one is in the first link and then the second two are just for the ampt/tone and the tuner(somewhat irrelevant). It's not exactly worth much effort-wise as it doesn't have a great reputation and I certainly don't need it. so may just pass on to someone else for fun and tinkering
 
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