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KrisBlueNZ
Sadly passed away in 2015
OK, there's not enough bias in either of the output stages. I think the resistor fuses might be the cause. Can you temporarily install four low current fuses, e.g. between 100 mA and 500 mA, fast blow, instead of the resistor/LED fuses, and re-measure those voltages please.
Ahhhh you know that never crossed my mind! Will do this tomorrow evening after work,
Have a confession to make, I only currently have two of the four resister fuses installed, I had a fault with one of them and it was bringing the fault right LED on, and forgot to put them back , sorry !!
Have a confession to make, I only currently have two of the four resister fuses installed, I had a fault with one of them and it was bringing the fault right LED on, and forgot to put them back , sorry !!
for the LEFT chanel i mesured from T4 to D10 and it reads 02.0m and keeps going up and down the longer i hold the probes on,
Q1 = 0.59VDC
Q10=0.60VDC
Q12=0.61VDC
Q18=0.18VDC
Q22=0.58VDC
Q11=
Q13=
Q20=
for the RIGHT chanel i mesured from T4 to D32 and it reads 023m
Q23=
Q25=
Q26=
Q28=
Q40=
Q37=
Q34=
Q36=
you know when you get that feeling when something is going to take a while aaaaaahhhhhhh!!!!!!!!!!!!!!!!!!!!!!!!!!
#SICKASF**K!!
Q1 = 0.59VDC
Q10=0.60VDC
Q12=0.61VDC
Q18=0.18VDC
Q22=0.58VDC
Q11=
Q13=
Q20=
for the RIGHT chanel i mesured from T4 to D32 and it reads 023m
Q23=
Q25=
Q26=
Q28=
Q40=
Q37=
Q34=
Q36=
you know when you get that feeling when something is going to take a while aaaaaahhhhhhh!!!!!!!!!!!!!!!!!!!!!!!!!!
#SICKASF**K!!
KrisBlueNZ
Sadly passed away in 2015
What happened? Which components burned up?
Think I must have shorted Q11 somehow, C9 has gone R30, R32, and a couple of smaller components , will make a list of exactly burned, all the tracks are ok on the underside of the board so it's just a case of replacing the damaged ones and a clean up, hope the drivers haven't been damaged!
Not going to lie, it looked like a Roman candle!
Not going to lie, it looked like a Roman candle!
EDIT:
Obvious resistors that have disintegrated are
R30
R32
R89
R23
R21,
Think there will be others to,
I have already got the replacements apart from R30 and R32 maplins did not have them, as per!
Last edited:
Or would these be better? The ± is different is doesn't say on the schematic what the ± is on the originals!
http://pages.ebay.com/link/?nav=item.view&alt=web&id=281562924764
http://pages.ebay.com/link/?nav=item.view&alt=web&id=281562924764
KrisBlueNZ
Sadly passed away in 2015
The tolerance isn't critical - ±5% would be fine, though nowadays most resistors are ±1%. But R30 and R32 need to be rated for 1W power dissipation. Either of those options would be fine.
ok all the burned componants replaces and the board cleaned up best i can,
the drivers are both dead!!
would these be ok for replacements
http://www.ebay.co.uk/itm/2SA1859A-...Supplies_ET&hash=item2edd23c62b#ht_270wt_1160
http://www.ebay.co.uk/itm/2SC4883A-...Supplies_ET&hash=item2edd23bd55#ht_358wt_1160
the amp is powering up ok with no fault LED'S
the drivers are both dead!!
would these be ok for replacements
http://www.ebay.co.uk/itm/2SA1859A-...Supplies_ET&hash=item2edd23c62b#ht_270wt_1160
http://www.ebay.co.uk/itm/2SC4883A-...Supplies_ET&hash=item2edd23bd55#ht_358wt_1160
the amp is powering up ok with no fault LED'S
KrisBlueNZ
Sadly passed away in 2015
Yes, they look suitable, if that's what they really are - semiconductor counterfeiting is alive and well on eBay - all you can do is hope!
KrisBlueNZ
Sadly passed away in 2015
Digi-Key deal directly with manufacturers or their authorised agents. They still occasionally get caught out, but they're a much better option than eBay.
Personally I would replace any component that may have been stressed, and I would always replace complementary transistors as a pair unless they were very expensive.
Personally I would replace any component that may have been stressed, and I would always replace complementary transistors as a pair unless they were very expensive.
Ok I gave in and went with Digikey,
Should be here soon, when they arrive should I fit them and the fast blow fuses and carry on where I left off, or would you like me to take some more measurements befor I fit them?
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