yammie CR-1040/overload lite lit

jkcoondog3

Active Member
I have a CR-1040 that I've used off and on. Loaned it it my Brother in law which can pretty much destroy an anvil with a rubber mallet and it went into overload mode. I have it back now since it is broken and would like to know where to start on fixing it. Does it have a reset button? I didn't notice any blown capacitors. Brother in law said it made a crack or snap as if someone hit a window with a rock before it went out. Any help would be appreciated. I think ROBISME had a couple of posts on this issue. Did ROBISME ever get his fixed? thanks
 
Reset Button?? Ahh no. Probably has a shorted hybrid output IC.
 
Last edited:
Can't miss them. Big, black, multi-pin plastic packs mounted on the aluminum heatsink.
 
Is IC 601 and 602, rectangular boxes that say pre-driver on them the ones you're talking about? If these are no longer able to get does this mean the receiver is junk. AS in boat anchor.
 
:yes: Need to check the voltages on each one of the pins of both STK0080II's

Just in case..
http://www.bdent.com/SearchResults.asp?Search=STK0080II+&Search.x=12&Search.y=8

i have a volt meter but not quite sure how to use it. What setting do i set the volt meter on? Its an auto ranging craftsman digital voltmeter. I have the panel off the bottom of receiver and can see the 10 pins on each. Do I put black lead to ground and probe each pin with red lead? Is this done with the unit on? Pardon me for my ignorance when it comes to this techie stuff, but if led in the right direction I think I can do this. I'd like to fix this receiver but limited to my knowledge. I can solder pretty well. I thought them yammie proprietory IC's where next to impossible to get. thanks for the help I need all I can get. So far after being a member for awhile I have learned and even fixed a couple of receivers but still learning
 
Do I put black lead to ground and probe each pin with red lead? Is this done with the unit on?
Yes,yes. Using the DC volts range on your meter. Be extremely careful not to short any adjacent pins together on the modules when making voltage measurements. The pins are labeled 0 - 9. Post the voltages you get.
 
Last edited:
Yes,yes. Using the DC volts range on your meter. Be extremely careful not to short any adjacent pins together on the modules when making voltage measurements. The pins are labeled 0 - 9. Post the voltages you get.

Ok here is what I got. starting with STK0070 which is closest to front of receiver I've got on pin 1= 049.5/ pin2= -052.4/ pin3= 049.4/ pin4= 2.9/ pin5 meter just jumps all over, never get an accurate reading/ pin6 same as 5/ pin7= 2.6/ pin 8=049.4/pin 9=052.6/ pin 0=050.4 rear stk-0080 pin1=-1.73/ pin2=-052.6/ pin3=-0.561/ pin4=015.5/ pin5=015.8/ pin6=012.2/pin7=012.7/ pin8=0.527/ pin9=052.6/ pin0=0.636. Oh BTW, when my brother in law blew it up he said it made a hell of a noise before no sound as if rock hit the side of a trailer. I checked for blown caps but couldn't find anything.
 
Well, a buddy now has mine. He runs it in mono with a speaker connected to A left and one to B left. The problem with mine was the preamplifier IC pack for one channel. It would pass high DC keeping in protection. I pulled it and the receiver plays fine. (out of one channel).

The IG02950, I think it was, is very very hard to find.

I tried the good predriver in both channels and it worked.

I have to leave work now, so I will try to be of more help later.

The pop is odd.

Rob
 
pop noise was probably the speaker blowing up ..
them stk.s i normally take out of circuit and check for shorted pins first .. did it blow both channels i wonder
 
Seems I confused the CR-640 I worked on with the CR-1040. The 640 was the one with the IG02950's.

The 1040 was missing a predriver. The good one went to an AK'er.

I would still bet the predriver let a bunch of DC through. Could have been the speaker popping with the DC.

Do follow the thread by Merrylander. He is the Yamaha guy, AFAIC.

Rob
 
cr-1040 ic's

i believe i still have some nos ic's for the cr-1040 both the pre driver and main power ic,picked them up on ebay many years ago and i used a few sets to repair some of my 1040's,though i will have to pray to the parts gods that i can still find them. let me know if you have need and ill see what i can do
 
i did a quick search on google and found someone on craigslist that has 23 ic's some yamaha for sale i used the search yamaha ig02960 to find it,i also found a few vendors that have NOS yamaha ic's using same search parameters hopefully they have the one's you need
 
I recently bought John's (coondog) 1040 and have thus inherited this problem, but really want to get this old beast going again. I'm new to AK, so bear with me, but here's what I get when testing pre-drivers and adjusting voltage offset:

Front Pre-Driver
Pin 13: 49.7
Pin 14: 50.3
Pin 15: 50.9

Rear Pre-Driver
Pin 13: -1.24
Pin 14: 1.21
Pin 15: 50.8

Voltage offset
TP1: 49.3 V does not respond to VR adjustment
TP2: 0.003 V after adjustment


According to merrylander's diagnostic criteria, the front pre-driver is toast. I know they're rare as hen's teeth, but does anyone have a pre-driver? Also, how do I test the power amps to be sure they're ok?
 
Back
Top Bottom