amp chip inside Sanyo M-X720K
- Thread starter k2j
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baddboybill
Boomus Fidelis
baddboybill
Boomus Fidelis
What's the symptomsk2j said:I think its blown, need to look up the datasheet in order to test it... Pleeez do tell
Bad quality sound. I can just about turn it all the way up and the sound is very blah, no bass and too quiet IMO. that is with radio or line-in input. Line-out sounds good on blockbusters input.
Originally I thought the speakers might be blown or out of phase so I hooked them up to my blockbuster and they sound KILLER.
I've deoxed all the switches and they seem to be working properly.
Next I figured I'd check the VCC at the power amp to see if it was getting proper power. Tried running off AC/DC and also tried test bench DC power supply direct to battery leads.
Bit of a puzzler. Let's put it this way, my M-X620K puts it to shame
Originally I thought the speakers might be blown or out of phase so I hooked them up to my blockbuster and they sound KILLER.
I've deoxed all the switches and they seem to be working properly.
Next I figured I'd check the VCC at the power amp to see if it was getting proper power. Tried running off AC/DC and also tried test bench DC power supply direct to battery leads.
Bit of a puzzler. Let's put it this way, my M-X620K puts it to shame
Plug up the 720 using the AC cord. If the VU for battery level isn't all the way to the right, then you probably still have a dirty power switch. The 720 I had was notorious for getting a dirty power switch. It pretty much had the same symptoms as you are describing. Just a thought...
baddboybill
Boomus Fidelis
mine too
Ok, got 'er rigged up to test...looks like the left needle goes just to the '1'. are you saying it should peg over past the '+5'? or is 1 correct?
Also, I have sprayed it quite a few times with deoxit and now it seems to be almost puddled in there. Does this stuff ever evaporate? sheesh
Thanks for the help guys!
Also, I have sprayed it quite a few times with deoxit and now it seems to be almost puddled in there. Does this stuff ever evaporate? sheesh
Thanks for the help guys!
baddboybill
Boomus Fidelis
There is actually a double switch in the 720. A regular silver and a black micro switch next to it. The black one usually is dirtiest. I took my board completely out to get into switch better. The cleaner will dry but don't plug in for a while to make surek2j said:Ok, got 'er rigged up to test...looks like the left needle goes just to the '1'. are you saying it should peg over past the '+5'? or is 1 correct?
Also, I have sprayed it quite a few times with deoxit and now it seems to be almost puddled in there. Does this stuff ever evaporate? sheesh
Thanks for the help guys!
Ok. Wow! Not only is it MUCH better sounding, but I actually have bass and treble control!!! 
I ended up replacing about 1/3 of the caps on the main PCB (all the caps within the vicinity of the power amp). So I'm not quite sure if it was that or the respraying of deoxit on the power and bass/treble pots....Probably a combo of both.
here is some pics of the cap replacement. It still doesn't have the brutal piercing highs that my recapped blockbuster has, but WOW is it warm and fuzzy sounding!
Thanks bill and fatdog for the advice!
Wow! Not only is it MUCH better sounding, but I actually have bass and treble control!!! I ended up replacing about 1/3 of the caps on the main PCB (all the caps within the vicinity of the power amp). So I'm not quite sure if it was that or the respraying of deoxit on the power and bass/treble pots....Probably a combo of both.
here is some pics of the cap replacement. It still doesn't have the brutal piercing highs that my recapped blockbuster has, but WOW is it warm and fuzzy sounding!
Thanks bill and fatdog for the advice!
baddboybill
Boomus Fidelis
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