Harman Kardon 330b Receiver - blowing main fuse Help!

[dlucy]

Sorry ... I picked up my manuals from here http://www.hifiengine.com/manual_library/harman-kardon/330.shtml

That is the correct place to get the manuals. You should visually inspect your circuit boards and compare what you see to the diagrams in the service manual and the addendum. Choose the manual based on the actual components inside your receiver rather than assuming the serial numbers are accurate.

I can post more images of the boards inside the units I have if you need help identifying which one you have.

 

[Quang Nguyen]

Thank you dlucy, I am at work right now and I will check again once I come home from work (and my wife allows me to go to my mancave). Thanks for all the tips. I paid $40 for the amp and don't really want to pay more than that to get it working again. I still have my Sansui Classique A-700 to play my R2R tapes ...

 

[dlucy]

The schematic for my 330B called for (4) 2SC1107 output transistors, but someone had already replaced those with TIP31BG transistors. One or more of mine were blown, so I removed all of them.

Finding replacement 2SC1107 devices will not be easy and finding a reputable source (so you don't get fakes or faulty ones) will make it harder. Unless you have some reason to keep the exact original components in place, I recommend you replace all four with MJE15030G transistors. They have the proper BCE/ECB pin order so they can be attached to the heatsink just like the 2SC1107 transistors and they have much better specs than the 2SC1107's.

 

[dlucy]

Thank you dlucy, I am at work right now and I will check again once I come home from work (and my wife allows me to go to my mancave). Thanks for all the tips. I paid $40 for the amp and don't really want to pay more than that to get it working again. I still have my Sansui Classique A-700 to play my R2R tapes ...

If you were to replace all the caps and all the transistors on the main amp, assuming the problems were limited to that one board, you'd be looking at about $32 in parts (from Mouser):

C401 Nichicon 647-UKL1V100MDDANA
C402 Nichicon 647-UKL1V100MDDANA
C403 Nichicon 647-UPW1V221MPD6
C404 Nichicon 647-UPW1V221MPD6
C405 Nichicon 647-UPW1V221MPD6
C406 Nichicon 647-UPW1V221MPD6
C407 Nichicon 647-UKL1V100MDDANA
C408 Nichicon 647-UKL1V100MDDANA
C409 Nichicon 647-UPW1J470MPD
C410 Nichicon 647-UPW1J470MPD
C417 Nichicon 647-UPW2A010MDD
C418 Nichicon 647-UPW2A010MDD
C419 Nichicon 647-UKL1V222KHD
C420 Nichicon 647-UKL1V222KHD
Q401 Fairchild 512-KSC3503DS
Q402 Fairchild 512-KSC3503DS
Q403 Fairchild 512-KSC1845FTA
Q404 Fairchild 512-KSC1845FTA
Q405 Fairchild 512-KSC1845FTA
Q406 Fairchild 512-KSC1845FTA
Q407 Fairchild 512-KSC2690AYS
Q408 Fairchild 512-KSC2690AYS
Q409 Fairchild 512-KSA1220AYS
Q410 Fairchild 512-KSA1220AYS
Q411 ON Semi 863-MJE15030G
Q412 ON Semi 863-MJE15030G
Q413 ON Semi 863-MJE15030G
Q414 ON Semi 863-MJE15030G
VR401 Bourns 652-3309W-1-104
VR402 Bourns 652-3309W-1-104
VR403 Bourns 652-3309W-1-502
VR404 Bourns 652-3309W-1-502

If you carefully test all the above components, you may well find you don't need but those few faulty parts.

If the output transistors do need to be replaced, you'll need TO-220 style mica insulators and some Thermalloy thermally conductive heatsink grease for when you install the new output transistors.

TO-220 INSULATOR 534-4673
THERMALCOTE 2 OZ 532-250

 

[petehall347]

it would also be best to renew the 0.47 ohm emitter resistors whilst you are in there . blown outputs and simply old age would have stressed them .

 

[Quang Nguyen]

Thank you all for your tremendous help on this. The last time I use a multimeter (Fluke) was in 1988 when I was working as a PC Designer for IBM PS/2 series so my skill is for sure a bit rusty. I also need to review my electronic courses back in the 80's... I will attack this HK 330B this weekend ... and report back. Thank you so much. Oh, it also takes sometime for Mouser to ship too ... so it may be a few weeks more ...