problem with right channel on fisher reciever...

D

daseraces13

Enthusiast
Ratings
2
#1
hello everyone, i have a fisher rs-1052 reciever. it sounds quite amazing in comparison to my old jvc r-2x. the problem with the reciever is the right channel would sometimes cut out and lower in volume in comparison to the left channel. oddly enough, if you were to hit the top of the reciever .. POP its back. didnt worry about it because it happened not too often. fast forward 3 months i remember opening up this reciever and seeing many blown caps. so, i replaced all of the caps. the left channel works fine as always(and what a sound improvement),but the problem with the right channel got worse... a lot worse. its always at that very low volume, almost cant hear it when the volume is at max.. so, i hit the top of it again and no luck, lol. so i took the cover off and started tapping boards with the handle of a screwdriver to see if anything changed, and the board with the heat syncs seems to be where my issue is.. if i lightly tap anywhere on the board it comes back right away. i am confused past my knowledge. could it be a cold solder joint from when i replaced the caps? an old solder joint among the ones i didnt touch? loose connection(thats whag im thinking)? i am stuck. anyones help is greatly appreciated. thank you.
 
M Code

M Code

Audioholic Chief
Ratings
464 1
#2
Wow.. Oldie but goodie..
That receiver was built by Hitachi and is 30 years old..
Suggest U check the connectors on the PCBs these often work loose with age and/or transit. Also a good thing to do is to pop off the connectors and then reinsert them as they can over age oxidize the terminals giving a weak connection. Pulling them off/on tends to burnish the contact surface..

Just my $0.02... ;)
 
D

daseraces13

Enthusiast
Ratings
2
#4
Wow.. Oldie but goodie..
That receiver was built by Hitachi and is 30 years old..
Suggest U check the connectors on the PCBs these often work loose with age and/or transit. Also a good thing to do is to pop off the connectors and then reinsert them as they can over age oxidize the terminals giving a weak connection. Pulling them off/on tends to burnish the contact surface..

Just my $0.02... ;)
thanks for the reply, what are you referring to when you say pcb? and what connectors are you referring to?
 
KEW

KEW

Audioholic Warlord
Ratings
4,311 22 4
#6
PCB is printed circuit board.
I suspect he is talking about anyplace where a wire (single or as part of a harness) connects to a circuit board. Hopefully M Code will be back with more specifics for vintage consumer electronics, but they often have a plastic connector that snaps into place and often requires some type of release be activated before removal like these:
https://www.google.com/search?q=pri...sPjdAhUSmeAKHRlABKUQ_AUIDigB&biw=1366&bih=657
 
TLS Guy

TLS Guy

Audioholic Slumlord
Ratings
7,226 17 24
#7
There is likely one of three problems.

A bad connection on a wire leading to the amp board, a break in the PCB board, or a bad connection in the hybrid IV power amp chip.

Those were downmarket units sold under various brands including the SEAS house brand. Claim is 52 watts per channel, but I doubt it. At that tome output THD were not specked and actually often rated at 10% THD on those sort of units.

So check all the connectors and clean them. Then carefully tap on the Sanyo SS 1001 power amp IC of the offending channel. This is quite likely to be the problem as these were very cheap indeed power amp chips.

If that is the problem there are still a few available from eBay sellers.

If that fails you will have to remove that board and look for any circuit breaks and dry joints.

That unit is certainly not worth a lot of trouble or expenditure. That is from an era when receivers were in marked decline and a far cry from the "battle ship" receivers of the earlier glory days. When it comes to those older Far Eastern receivers, then in general the older the better.
 
D

daseraces13

Enthusiast
Ratings
2
#8
well i solved it so far... tore it apart again and looked at the suspect board’s pcb and i didnt notice there were many globs of solder in places i didnt even touch... so out came the solder wick and i made that neater. then started inspecting and i saw where the board had delaminated near a solder joint... i neatened that up to my best ability and it doesnt cut out anymore, ive been tapping around and nothing is wrong. so i guess i fixed it? thanks all for their help.
 
D

daseraces13

Enthusiast
Ratings
2
#9
well as soon as i sent that it stopped working... blew 2 fuses. assuming for the left and right channel. what could cause that?
 
TLS Guy

TLS Guy

Audioholic Slumlord
Ratings
7,226 17 24
#10
well as soon as i sent that it stopped working... blew 2 fuses. assuming for the left and right channel. what could cause that?
That is probably bad news. I suspect in soldering the board you have created some sort of stray solder whisker that has caused some sort of short. The question is how much damage has it done. Unfortunately solid state circuitry is very intolerant of this sort of misshap, and more likely than not you have widespread damage.

I would look closely for any stray bits of solder, and check for elimination with your meter. Then replace the blown fuses once. If they blow again, it is realistically the end of the road for that unit.

The other possibility is that you were so enthused after your reapair, you pushed the amp hard, and have blown those old IC chips. The failure mode is always shorted output stage which blows the fuses. Those old hybrid IC power amps, where never tolerant of being driven hard and never tolerated loads below 6 ohms. They are worse as they age. Most of those old units are long gone. They really never where anything to write home about, and that putting it kindly.
 
D

daseraces13

Enthusiast
Ratings
2
#11
That is probably bad news. I suspect in soldering the board you have created some sort of stray solder whisker that has caused some sort of short. The question is how much damage has it done. Unfortunately solid state circuitry is very intolerant of this sort of misshap, and more likely than not you have widespread damage.

I would look closely for any stray bits of solder, and check for elimination with your meter. Then replace the blown fuses once. If they blow again, it is realistically the end of the road for that unit.

The other possibility is that you were so enthused after your reapair, you pushed the amp hard, and have blown those old IC chips. The failure mode is always shorted output stage which blows the fuses. Those old hybrid IC power amps, where never tolerant of being driven hard and never tolerated loads below 6 ohms. They are worse as they age. Most of those old units are long gone. They really never where anything to write home about, and that putting it kindly.
thanks for the input, ill check it out tonight
 
D

daseraces13

Enthusiast
Ratings
2
#12
That is probably bad news. I suspect in soldering the board you have created some sort of stray solder whisker that has caused some sort of short. The question is how much damage has it done. Unfortunately solid state circuitry is very intolerant of this sort of misshap, and more likely than not you have widespread damage.

I would look closely for any stray bits of solder, and check for elimination with your meter. Then replace the blown fuses once. If they blow again, it is realistically the end of the road for that unit.

The other possibility is that you were so enthused after your reapair, you pushed the amp hard, and have blown those old IC chips. The failure mode is always shorted output stage which blows the fuses. Those old hybrid IC power amps, where never tolerant of being driven hard and never tolerated loads below 6 ohms. They are worse as they age. Most of those old units are long gone. They really never where anything to write home about, and that putting it kindly.
you were right, solder jumped from one land to the other.... i fixed it and checked everywhere else, now i have to get my hands on a 6A slow fuse and see if i damaged anything or if the fuse saved it.. ill let you guys know
 
M Code

M Code

Audioholic Chief
Ratings
464 1
#13
Note that receiver is very sensitive to grounds.. I recall that both the Right & Left channel speaker output negative terminals were not common and above ground...

Just my $0.02... ;)
 
Last edited:
D

daseraces13

Enthusiast
Ratings
2
#14
well i have some bad new.... i plugged in a new reciever for the time being (jvc r-2x) and started playong and the woofer on my top right speaker was dead... i have 4 wharfedale s77 towers, 32 inches tall. 900 dollar speakers each back in 82. anyways, i turn the volume up and it starts to crack when theres supposed to be bass.... pulled the woofer out and its completely siezed and i couldnt be more bummed.. the magnet on this woofer is more than half the size of the cone and very thick. im assuming the voice coil over heated and its obviously shot. i have to order sone new fuses for the reciever and try it on some other speakers and hope it doesnt fry that. if it does that would be very sad ;(
 
M Code

M Code

Audioholic Chief
Ratings
464 1
#15
well i have some bad new.... i plugged in a new reciever for the time being (jvc r-2x) and started playong and the woofer on my top right speaker was dead... i have 4 wharfedale s77 towers, 32 inches tall. 900 dollar speakers each back in 82. anyways, i turn the volume up and it starts to crack when theres supposed to be bass.... pulled the woofer out and its completely siezed and i couldnt be more bummed.. the magnet on this woofer is more than half the size of the cone and very thick. im assuming the voice coil over heated and its obviously shot. i have to order sone new fuses for the reciever and try it on some other speakers and hope it doesnt fry that. if it does that would be very sad ;(
Hmmm.. Sorry to hear the bad news. I doubt if replacement parts are available and even if yes, most likely expensive. Note that many years back in the 80s', I was the VP Marketing for the Wharfdale USA distributor, they were a great product in their day...

Just my $0.02... ;)
 
TLS Guy

TLS Guy

Audioholic Slumlord
Ratings
7,226 17 24
#16
well i have some bad new.... i plugged in a new reciever for the time being (jvc r-2x) and started playong and the woofer on my top right speaker was dead... i have 4 wharfedale s77 towers, 32 inches tall. 900 dollar speakers each back in 82. anyways, i turn the volume up and it starts to crack when theres supposed to be bass.... pulled the woofer out and its completely siezed and i couldnt be more bummed.. the magnet on this woofer is more than half the size of the cone and very thick. im assuming the voice coil over heated and its obviously shot. i have to order sone new fuses for the reciever and try it on some other speakers and hope it doesnt fry that. if it does that would be very sad ;(
Obviously that receiver had no protection from DC off set. The output device of that channel is broken down and the DC rail voltage is connected to the speaker though the output devices. You fried the woofer by exposing it to the DC rail voltage and burnt out the VC.

Do not replace the fuses until you replace the output IC of that channel and then replace the fuses. However you will need to bring the receiver up on a variac and monitor for DC offset before connecting to any speaker, or you will fry another speaker.

If this repair is beyond your expertise then that receiver is done.

Truthfully if you value your speakers you do mot want to use that receiver. A lot of gear of that era did not have DC offset protection at the output to the speakers, and that one obviously does not. So I would ditch it.
 
highfigh

highfigh

Audioholic Warlord
Ratings
2,634 9 4
#17
Wow.. Oldie but goodie..
That receiver was built by Hitachi and is 30 years old..
Suggest U check the connectors on the PCBs these often work loose with age and/or transit. Also a good thing to do is to pop off the connectors and then reinsert them as they can over age oxidize the terminals giving a weak connection. Pulling them off/on tends to burnish the contact surface..

Just my $0.02... ;)
I wonder why Hitachi would have built that when the company was owned by Sanyo.
 
M Code

M Code

Audioholic Chief
Ratings
464 1
#18
I wonder why Hitachi would have built that when the company was owned by Sanyo.
Don't know exactly... But back then Fisher was dominating the component rack system biz being sold by the department stores...

Just my $0.02... ;)
 

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