punch 60 ix pc-0764

[swedude]

hi im totally new on this grait forum.well to the problem.i just picked up a Rockford as described in title, from a box that been laying around for maby 15-20 years!! i just feel for try repair it again.but im not sure what outputfets it had course i left it half dissasembled last time.i got a schematic from net but it dosent are equal to the board.on my board its only a pair of outputfets but on chematic its 2 for eatch channel.do any have chematic for this one.the problem i can remember was the fets on output gone, and after new one installed them got hot very fast.it seems like i have done some Changes Before course on Power board its irfz44 and i see i have changed some resistors to 68r near the transformer.the Power side is ok, i can get it on to led.(no fets is on the board on output now.if i remember right i broke it by showing some people the filterpass card, and forget to turn off the system.(wery stupid i know)

 

[Perry Babin]

http://www.bcae1.com/temp/rockford - punch60ix pc-0764f.pdf

 

[swedude]

Thanks a lot Perry.it seems to bee the right one.if you have any ideas about the problem i,ll be glad. It so longt time ago i did this things so i start to feel like im learn how to run a bike again i Think it just to start up the meter and start to measure the transistors in line with the buz11, then.sorry for my Little bad English.

 

[swedude]

HI AGAIN i have done some measuring,first some info.the amp have all the buz11 desoldered.and the dc-dc power works,so i can start the amp.I start to test left channel komponents. q112 is b=-12,27v c=-0,53v e=-13,91v ? and the q113 gives from -13,2 to -14,38 on all legs.from right to left legs it increase..measur the pads of buz 11 gives on q142 g=+1,665v d=+27,35 and s=+3,5mv on q143 i get g=-22,92 d=3,5mv(not sure if it was negative of not) and s=-27,27v and it almost the same result for right channel.alsp q114 give me headace i got around 13v om both base and emitter but less then 0,5 on collector. anyone have any ideas? by the way i got one homehifi amp worked today..

 

[Perry Babin]

You cannot use voltage to troubleshoot inside the feedback loop if the loop isn't complete (it's not complete without the output transistors in the circuit).

Q114 voltages should be near -13, not +13.

 

[swedude]

ok så maby i can put on new buz11 and Quick measure then? Before it gets to hot.oohh i belive it was netative on q114.well you seens to know a lot about this, maby you know common problems on this amps outside the putputs and the irfz44.a blown.first time a repaird it it has buz or 44 blown, i cant remember witch of it, time goes fast 15-20 years poff

 

[Perry Babin]

Do you still have the output transistors you removed from the amp? If so, re-check them. Which ones have failed?

 

[swedude]

no. i cant find them so i guess i trow them away.i have order 10 new but dont have them yet.but i have a lot of irfz44 at home,but gess i cant use them for output on this amp.really havent checked. will you rekoned test q112-113 by ohm or diode test?i have one appa 69mutimeter to test with.i have been gone for so long from this so i dropped a lot.but Think this is fun and stimulates the brain.

 

[Perry Babin]

I don't understand the question.

 

[swedude]

i meant ,what is best to measure the transistors on board when i got no Power to it.use ohm,s or diodetest,i often use diotest because the transistors have diods in them.

 

[Perry Babin]

There is no way to get definitive readings in the board unless the transistor is shorted or very leaky. If you don't find any shorted, you can go to ohms and compare readings from one channel to the other for corresponding parts.

 

[swedude]

i got the parts for the amp now,im in to change the mps6521 and the buz11.is it safe to test it with a 5a Power supply?.

 

[Perry Babin]

If all heatsink mounted components are clamped tightly to the heatsink, there will be very little risk to them with a 5 amp power supply.

 

[swedude]

i measured the mps6521 again and they seems ok.did Clean hole board with acetone using cuttonpins and blow some air.then solder in new buz11 and clamped them and IT WORKS!!!.just test with a lose speaker so nor mutch Power or highlevel.but it sounds ok i guess.now,then dissasembled all again to put in new paiste..this is old amp and i thinking about change all the smd elytcaps to get it in good condition.is this a god idea or bad, im little worry to mess something up.ps i guess last time i had bad fets or short/conductive somewhere.well thanks for all support.the swede Went happy as a kid at the candystore

 

[Perry Babin]

If you apply heat with the soldering iron to the leads on the SMD caps, do you smell burning electrolyte?

 

[swedude]

havent try yet,but after serius inspection with increase glasses i dont see any leaks.

 

[swedude]

and i dont really remember hows elyt smells,maby have to put in a little cap on the dc Power reverse so i can remember the smell .)

 

[Perry Babin]

People describe it as smelling like anti-freeze or fishy.

 

[swedude]

can i use coldspray and ohm mesure to see if its have to be change?i guess that use the caps mesuring )capacitans) can do harm to other Components.right?

 

[swedude]

unless there is short ,what other ways is it to measure caps when they are in ciruits? off topic have u seen the old Movie short circuit,the robot.old but grait.