sx-1250 power amp SMOKED help

O.K. Here is a list I found of the resistor part numbers for awh-048 posted from you MTF. The readings from all the resistors on my "smoked" board are at the end. I removed one pin on each part before checking. I was gonna replace all of them but think I will just do what is necessary as a learning tool for myself.


Pioneer SX-1250
Power Amplifier Assembly (AWH-048) Resistor List:

R1: 3.3K Carbon Film: 660-CFS1/4CT52R332G ----- (3.326)
R2: 220K Carbon Film: 660-CFS1/4CT52R224J ----- (218.7)
R3: 82 Carbon Film: 660-CFS1/4CT26A820G ----- (81.8)
R4: 47K Carbon Film: 660-CFS1/4CT52R473G ----- (46.7)
R5: 47K Carbon Film: 660-CFS1/4CT52R473G ----- (46.7)
R6: 82 Carbon Film: 660-CFS1/4CT26A820G ----- (80.6)
R7: 62K Carbon Film: 660-CFS1/4CT52R623G ----- (61.6)
R8: 200K Carbon Film: 660-CFS1/4CT52R204J ----- (198.6)
R9: 100 Carbon Film: 660-CFS1/4CT52R101G ----- (9.7)
R10: 100 Carbon Film: 660-CFS1/4CT52R101G ----- (100.1)
R11: 16K Carbon Film: 660-CFS1/4CT52R163G ----- (16.07)
R12: 16K Carbon Film: 660-CFS1/4CT52R163G ----- (16.07)
R13: 1.5K Carbon Film: 660-CFS1/4CT52R152G ----- ( 1.510)
R14: 62K Carbon Film: 660-CFS1/4CT52R623G ----- (061.6)
R15: 220 Carbon Film: 660-CF1/4CT52R221G ----- (219.3)
R16: 220 Carbon Film: 660-CF1/4CT52R221G ----- (215.8)
R17: 1K Carbon Film: 660-CFS1/4CT52R102G ----- ( 0.981)
R18: 47 Carbon Film: 660-CFS1/4CT52R470G ----- (47.5)
R19: 47 Carbon Film: 660-CFS1/4CT52R470G ----- (47.1)
R20: 620 Carbon Film: 660-CFS1/4CT52R621J ----- (0.609)
R21: 100 Carbon Film: 660-CFS1/4CT52R101G ----- (98.9)
R22: 100 Carbon Film: 660-CFS1/4CT52R101G ----- (98.5)
R23: 10K Carbon Film: 660-CFS1/4LT52R103G ----- (10.10)
R24: 100 Metal Oxide: 1W 279-ROX1G100R ----- ( 3.150)
R25: 100 Metal Oxide: 1W 279-ROX1G100R ----- (151.2)
R26: 1K Metal Oxide: 1W 660-MOS1CT52R102J ----- (0.996)
R27: 1K Metal Oxide: 1W 660-MOS1CT52R102J ----- (4.55)
R28: 0.5 Wire wound: 5W 71-CP5-J-0.5 ----- (000.5)
R29: 0.5 Wire wound: 5W 71-CP5-J-0.5 ----- (000.5)
R30: 22 Carbon Film: 660-CFPS1/4CT52R220G ----- ( 21.8)
R31: 22 Carbon Film: 660-CFPS1/4CT52R220G ----- (21.6)
R32: 0.5 Wire wound: 5W 71-CP5-J-0.5 ----- ( NO READING)
R33: 0.5 Wire wound: 5W 71-CP5-J-0.5 ----- (131.8)
R34: 22 Carbon Film: 660-CFPS1/4CT52R220G ----- (21.9)
R35: 22 Carbon Film: 660-CFPS1/4CT52R220G ----- (21.9)
R36 4.7 1W RN1H 4R7K 594-5073NW4R700J
R37 4.7 1W RN1H 4R7K 594-5073NW4R700J
R38: 10 Metal Oxide: 2W 660-MOS2CT52R100J ----- ( 10.0)
R39: 10 Metal Oxide: 2W 660-MOS2CT52R100J ----- (10.1)
R40: 1.2K Carbon Film: 660-CFS1/4CT52R122G ----- ( 223.3)
R41: 1.2K Carbon Film: 660-CFS1/4CT52R122G ----- ( 2.440)
R42: 13K Carbon Film: 660-CFS1/4CT52R133G ----- (13.16)
R43: 13K Carbon Film: 660-CFS1/4CT52R133G ----- ( 13.00)
 
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I posted my findings twice this morning and there not here?

oops, the second page started. lol
 
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Browser interaction. After posting go back to forum and click on the thread again for a fresh copy, your browser was probably bringing up an archived copy from your temporary file. Happens to me sometimes when I forget (so wrapped up in the post)... -- hey where did that post go???? -----

BBL for analysis... not enough time now to focus on details.... this is just a drive by post lol...
 
Here we go:

O.K. Here is a list I found of the resistor part numbers for awh-048 posted from you MTF. The readings from all the resistors on my "smoked" board are at the end. I removed one pin on each part before checking. I was gonna replace all of them but think I will just do what is necessary as a learning tool for myself.


Pioneer SX-1250
Power Amplifier Assembly (AWH-048) Resistor List:

R1: 3.3K Carbon Film: 660-CFS1/4CT52R332G ----- (3.326)
R2: 220K Carbon Film: 660-CFS1/4CT52R224J ----- (218.7)
R3: 82 Carbon Film: 660-CFS1/4CT26A820G ----- (81.8)
R4: 47K Carbon Film: 660-CFS1/4CT52R473G ----- (46.7)
R5: 47K Carbon Film: 660-CFS1/4CT52R473G ----- (46.7)
R6: 82 Carbon Film: 660-CFS1/4CT26A820G ----- (80.6)
R7: 62K Carbon Film: 660-CFS1/4CT52R623G ----- (61.6)
R8: 200K Carbon Film: 660-CFS1/4CT52R204J ----- (198.6)
R9: 100 Carbon Film: 660-CFS1/4CT52R101G ----- (9.7) huh??? I really HOPE not!!!
R10: 100 Carbon Film: 660-CFS1/4CT52R101G ----- (100.1)
R11: 16K Carbon Film: 660-CFS1/4CT52R163G ----- (16.07)
R12: 16K Carbon Film: 660-CFS1/4CT52R163G ----- (16.07)
R13: 1.5K Carbon Film: 660-CFS1/4CT52R152G ----- ( 1.510)
R14: 62K Carbon Film: 660-CFS1/4CT52R623G ----- (061.6)
R15: 220 Carbon Film: 660-CF1/4CT52R221G ----- (219.3)
R16: 220 Carbon Film: 660-CF1/4CT52R221G ----- (215.8)
R17: 1K Carbon Film: 660-CFS1/4CT52R102G ----- ( 0.981)
R18: 47 Carbon Film: 660-CFS1/4CT52R470G ----- (47.5)
R19: 47 Carbon Film: 660-CFS1/4CT52R470G ----- (47.1)
R20: 620 Carbon Film: 660-CFS1/4CT52R621J ----- (0.609)
R21: 100 Carbon Film: 660-CFS1/4CT52R101G ----- (98.9)
R22: 100 Carbon Film: 660-CFS1/4CT52R101G ----- (98.5)
R23: 10K Carbon Film: 660-CFS1/4LT52R103G ----- (10.10)
R24: 100 Metal Oxide: 1W 279-ROX1G100R ----- ( 3.150)
R25: 100 Metal Oxide: 1W 279-ROX1G100R ----- (151.2)
R26: 1K Metal Oxide: 1W 660-MOS1CT52R102J ----- (0.996)
R27: 1K Metal Oxide: 1W 660-MOS1CT52R102J ----- (4.55)

R28: 0.5 Wire wound: 5W 71-CP5-J-0.5 ----- (000.5)
R29: 0.5 Wire wound: 5W 71-CP5-J-0.5 ----- (000.5)
R30: 22 Carbon Film: 660-CFPS1/4CT52R220G ----- ( 21.8)
R31: 22 Carbon Film: 660-CFPS1/4CT52R220G ----- (21.6)
R32: 0.5 Wire wound: 5W 71-CP5-J-0.5 ----- ( NO READING)
R33: 0.5 Wire wound: 5W 71-CP5-J-0.5 ----- (131.8)
R34: 22 Carbon Film: 660-CFPS1/4CT52R220G ----- (21.9)
R35: 22 Carbon Film: 660-CFPS1/4CT52R220G ----- (21.9)
R36: 4.7 Metal Film: 1W 594-5073NW4R700J ----- (5.0)
R37: 4.7 Metal Film: 1W 594-5073NW4R700J ----- (5.1)
R38: 10 Metal Oxide: 2W 660-MOS2CT52R100J ----- ( 10.0)
R39: 10 Metal Oxide: 2W 660-MOS2CT52R100J ----- (10.1)
R40: 1.2K Carbon Film: 660-CFS1/4CT52R122G ----- ( 223.3)
R41: 1.2K Carbon Film: 660-CFS1/4CT52R122G ----- ( 2.440)
R42: 13K Carbon Film: 660-CFS1/4CT52R133G ----- (13.16)
R43: 13K Carbon Film: 660-CFS1/4CT52R133G ----- ( 13.00)

It really helps when you indicate the RANGE of the reading along with the reading, RANGE really IS part of the reading, otherwise it could be a factor of 10, 100 or 1000 off and still give correct digits - but in a bad range.

Overall, whew, that was some "lightning bolt" through the circuit - pre drivers and drivers as well as outputs blown, and the protection over current sense circuit as well.

please compare R9 and R10 color codes and do lifted leg resistance tests again, ...please... just for those two resistors.

resistance color code decoder
 
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I will check tonight. I'm pretty sure I wrote them down right. As for indicating the range what do you mean? I'm learning a bunch here and love it! I took apart my tv last night to try and repair an hdmi input. Also how do I determine the difference of what the circuits are? I mean like the pre drivers or outputs. I've read a lot of posts on different situations you have helped other people and I will say you have a lot of paitenence and obviously like teaching. It is very much appreciated Mark.
 
Also I tested the diodes last night by using a dmm and checked for current being allowed one way and not the other. There were a few letting current go both ways. For what they cost I am going to just replace them all. I'm still unsure on how to check the transistors like the Q7,Q8,Q9 and so on. I did check 4 of the main transistors on the heat sink and one of them allowed power to go both ways, the other three did not. I am going to replace them all. This units fm antenna has been robbed. The am/fm didn't work when I got it. I'm taking one step at a time repairing this but eventually want it to work as designed. I noticed some schaffed wires from a previous repair and the main caps have been replaced with the 17000 instead of the 22000 which I read are correct. If you have any leads on the antenna please let me know.I love repairing things! lol

My fiancé hates this radio !!!!!! It's taking me from her...
 
Mark wanted the resistance range stated as in the actual value. As: 1000 ohms could be written as 1K, or a 2500 ohm would be 2.5K. Below 1000 ohms we write as: 560 ohm would be 560. :D
 
tell us the exact make and model of your DMM, and we'll figure out what to tell you to watch for when reading resistances.

I love repairing things! lol

My fiancé hates this radio !!!!!! It's taking me from her...

That I cannot help with....

But once it's fixed, she should enjoy it with you.

She HAS to recognize this basic part of your nature....
 
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1. all transistors on the amp board(s) q1 - q11
2. all diodes on the amp board(s) (except the stv-3h's d1 and d2) d3 - d11 1n4148 & uf4004 see below:
3. all electrolytic caps on the amp board(s)
4. selected resistors - about 8 -- on the burned board

This is all comparatively inexpensive, and cheap insurance. About 20 bucks a board. For pretty much a new amp.

re: me... life happens.. don't see anything posted? - check if I am posting, and the depth of the posts that do occur. I've been occupied elsewhere and I don't LIVE in here. I used to, but that wasn't sustainable.

Now: I'm RE-reminding you to check the area of R8, R9 and R10, color codes and resistance values.
R9: 100 Carbon Film: 660-CFS1/4CT52R101G ----- (9.7) huh??? I really HOPE not!!!

sx-1250 awh-048l d3 1s1886 512-1n4004
sx-1250 awh-048l d4 1s1886 512-1n4004
sx-1250 awh-048l d5 1s2473 512-1n4148
sx-1250 awh-048l d6 1s1886 512-1n4004
sx-1250 awh-048l d7 1s1886 512-1n4004
sx-1250 awh-048l d8 1s2471 512-1n4148
sx-1250 awh-048l d9 1s2471 512-1n4148
sx-1250 awh-048l d10 1s1886 512-1n4004
sx-1250 awh-048l d11 1s1886 512-1n4004

Now I may add a few resistors besides the ones I ALREADY highlighted, so don't order yet - I have to curl up with a marked schematic and highlight the found damage and figure current paths (to find stressed resistors) and that will take more time than I have right now.
BUT
ALL the parts numbers needed are NOW in this thread with the addition of the diodes that I just did.

Here is a transistor testing method for gross faults.

BUT with burned up emitter resistors, the output transistors IF testing ok, AREN'T - they were racing each other and the resistors to destruction, and someone else won.

Here's the outputs which I just noticed aren't listed above:

........534-4662 to-3 mica insulators $0.19 each.................
863-MJ21193G pnp to-3 250v 16/30A 250W 8-75hfe 4mhz $5.87 / digikey $5.88
863-MJ21194G npn to-3 250v 16/30A 250W 8-75hfe 4mhz $5.87 / digikey $5.88
 
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thank you mark. I do know life happens and I'll tell ya repairing this radio sure does take a lot of the negative things off my mind! I have plenty. I purchased a list and got them today. I'll post part numbers soon. I tried to share the mouser list but couldn't figure out how. I'll double check r9 tonight.
 
Well I'm at the replacement of q1-q11 and want to make sure I am positioning these correctly. I know they look the same but I read somewhere that just because the flat spot goes the same direction doesn't mean the new part is the same. I've read a post somewhere on Audiokarma on this but can't find it now. Thanks again guys!
 
Well I'm at the replacement of q1-q11 and want to make sure I am positioning these correctly. I know they look the same but I read somewhere that just because the flat spot goes the same direction doesn't mean the new part is the same. I've read a post somewhere on Audiokarma on this but can't find it now. Thanks again guys!

You need to search for ECB on AK as there is only one way to correctly install a transistor and many wrong ways to install it. The data sheets for each transistor should be downloaded and the pin outs compared to the print out on the board.
 
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