I was at a local garage sale and picked up this H/K reciever for $10 being it didn't work. What happens is you power the unit on and the display comes on etc, and after a few seconds it just shuts down.
I haven't had time to even open the cover for the unit yet but I'm thinking maybe the outputs have shorted and when the amp is turning on it shorts and shuts off... that's my theory at least I've never played with one of these before
But I was hoping someone out there can get me a link to the repair manual. Any additional input or advice would be appriciated.
Cheers,
Tom
I haven't had time to even open the cover for the unit yet but I'm thinking maybe the outputs have shorted and when the amp is turning on it shorts and shuts off... that's my theory at least I've never played with one of these before
But I was hoping someone out there can get me a link to the repair manual. Any additional input or advice would be appriciated.
Cheers,
Tom
Well I finally got the thing brought into the shop and cracked open the lid. Nothing obvious, checked the rails after the bridge rectifier and was getting +/- 42V so that seems alright, I tried looking for the Emitter resistor but without taking the whole thing appart I'm not sure I'll have a chance of finding it. Ohmed the outputs and 2 come out into the MegOhms while 3 are around 17Kohms, not sure if that's weird or not.
Basically I'm still hoping and holding out that someone here can get me a schematic and possibly repair manual before I dive in, plus I'd like to snap a few digital pic's so I know how things go back together.
I did find out that if I press MUTE before the relay click that the unit will stay on and I can switch around the inputs and adjust the radio etc, but as soon as I un-mute the unit and the relay trips the thing shuts down. To me, that's saying there is probably a short after the relay, but I could totally be out to lunch.
Anyways, again any tips or hints are appriciated. Remember this is the first reciever I've played with so any help is welcome!
Basically I'm still hoping and holding out that someone here can get me a schematic and possibly repair manual before I dive in, plus I'd like to snap a few digital pic's so I know how things go back together.
I did find out that if I press MUTE before the relay click that the unit will stay on and I can switch around the inputs and adjust the radio etc, but as soon as I un-mute the unit and the relay trips the thing shuts down. To me, that's saying there is probably a short after the relay, but I could totally be out to lunch.
Anyways, again any tips or hints are appriciated. Remember this is the first reciever I've played with so any help is welcome!
Got the service manual! Thanks derguteton for the link
So that's good, I was checking over the schematics and trying to get familar with everything and understand what's going on when one of the guys I work with in the shop takes a peak inside, a min later says "You have a cracked emitter resistor."
Well... don't I feel stupid
ifrythings was pointing me in the right direction the whole time, the 5W 3 pin 0.27ohm resistor is destroyed and there is also a 1/5W 82ohm blown resistor, and a little more testing found the 2SA1695 is dead also, the complimentary 2Sc4468 seems to measure fine but if I can I'll replace it as well.
So, 3 bad parts thus far. Anyone out there know where I can find some replacement parts? The resistor and transistor are going to be somewhat tricky to find without paying alot. I'm debating trying to figure out a way to just run this reciever as a 2 channel instead of all 5, that way I can simply use the good parts from the other channels to make sure simply my right/left outputs work. I'll probably never use this for anything besides a shop reciever anyways, I have a much better home stereo setup already.
So that's good, I was checking over the schematics and trying to get familar with everything and understand what's going on when one of the guys I work with in the shop takes a peak inside, a min later says "You have a cracked emitter resistor."
Well... don't I feel stupid
ifrythings was pointing me in the right direction the whole time, the 5W 3 pin 0.27ohm resistor is destroyed and there is also a 1/5W 82ohm blown resistor, and a little more testing found the 2SA1695 is dead also, the complimentary 2Sc4468 seems to measure fine but if I can I'll replace it as well.
So, 3 bad parts thus far. Anyone out there know where I can find some replacement parts? The resistor and transistor are going to be somewhat tricky to find without paying alot. I'm debating trying to figure out a way to just run this reciever as a 2 channel instead of all 5, that way I can simply use the good parts from the other channels to make sure simply my right/left outputs work. I'll probably never use this for anything besides a shop reciever anyways, I have a much better home stereo setup already.
Well, since I got the service manual for the reciever I've been poking around, like I said above we figured out where the problem was comming from and I've got a few parts on order (nothing like free samples!) but some are proving to be a bit of a PITA to get for pretty much free.
So then I got to thinking... ... this is a 5 channel reciever with 5 seperate amplifiers... so check over the schematic and all the amps inside are a carbon copy of each other... Now this is an older reciever and the only way to get the authentic 5 channel outputs is to hook it up to a DVD player or what have you that has all 6 preamp outs, there are no digital inputs on this reciever.
So basically, for my purposes this reciever is useless as a 5.1 setup since I have a very nice home stereo already, this is going to be used mostly for my office or garage running stereo for the radio or a CD etc, so I really don't need to have all the amps working just the front right and front left, problem is the front right is the one that's blown.
So, doing a little double checking I was able to pull the +/- rails from the F.R. channel so it's dead and shouldn't cause anymore troubles, then bypass the input and go into the surround right amp and then again bypass the output so my right surround goes to the old F.R. channel output. So basically, I completely bypassed the FR amp and wired the SR amp to operate in it's place. Put it all back together, fired it up and it now stays on, hooked it up to a simple source off the comp and both channels work fine!
So for $10CAN I now have a Harman/Kardon stereo amplifier with 2 spare internal amps in case anything happens down the road. And if I ever get the parts in that I need to fix the amps, maybe I'll put it back to a 5.1 setup just for possible resale value.
I'm happy with it!
So then I got to thinking... ... this is a 5 channel reciever with 5 seperate amplifiers... so check over the schematic and all the amps inside are a carbon copy of each other... Now this is an older reciever and the only way to get the authentic 5 channel outputs is to hook it up to a DVD player or what have you that has all 6 preamp outs, there are no digital inputs on this reciever.
So basically, for my purposes this reciever is useless as a 5.1 setup since I have a very nice home stereo already, this is going to be used mostly for my office or garage running stereo for the radio or a CD etc, so I really don't need to have all the amps working just the front right and front left, problem is the front right is the one that's blown.
So, doing a little double checking I was able to pull the +/- rails from the F.R. channel so it's dead and shouldn't cause anymore troubles, then bypass the input and go into the surround right amp and then again bypass the output so my right surround goes to the old F.R. channel output. So basically, I completely bypassed the FR amp and wired the SR amp to operate in it's place. Put it all back together, fired it up and it now stays on, hooked it up to a simple source off the comp and both channels work fine!
So for $10CAN I now have a Harman/Kardon stereo amplifier with 2 spare internal amps in case anything happens down the road. And if I ever get the parts in that I need to fix the amps, maybe I'll put it back to a 5.1 setup just for possible resale value.
I'm happy with it!
Well as far as recievers go I've always been a Denon man, but for the price this one is a bit of a steal. It would be interesting to take this one home and listen to a CD on my Denon for awhile then swap this one in and hear for any differences. I've heard good things about the HK's but this is the first I've got to play with.
The guy I work with was the one who told me about this forum, he's collecting parts to build his own and I think he was eye'in up some of the guts of mine pretty seriously! nice beefy +/-40V transformer, decent heatsink setup...
I got thinking it would be fairly easy to incorperate my own amps into this unit down the road if I wanted, the layout is super simple and I could install my own amps in probably a couple hours and have all the functions of the reciever but with my gear installed!
I have a couple sticks of authentic 2SA1302 and 2SC3281 kicking around... this could be a very fun little cheap toy! Like I said the layout is super simple, basically the whole thing is just a simple switcher that selects which input to shoot to the amps and that's about it, if I build my own amps for inside everything is sitting there ready to go.
The guy I work with was the one who told me about this forum, he's collecting parts to build his own and I think he was eye'in up some of the guts of mine pretty seriously! nice beefy +/-40V transformer, decent heatsink setup...
I got thinking it would be fairly easy to incorperate my own amps into this unit down the road if I wanted, the layout is super simple and I could install my own amps in probably a couple hours and have all the functions of the reciever but with my gear installed!
I have a couple sticks of authentic 2SA1302 and 2SC3281 kicking around... this could be a very fun little cheap toy! Like I said the layout is super simple, basically the whole thing is just a simple switcher that selects which input to shoot to the amps and that's about it, if I build my own amps for inside everything is sitting there ready to go.
Identical problem...
Gotta love the internet.
BigTom, I've got the identical symptoms that you describe with my AVR5. I'd love it if you could shoot me any useful pics/docs that you have on the topic. I've opened it up, but I don't see anything amiss. Everything, down to the mute button, is the same as you describe it.
Although I'd like to fix the channel rather than reroute it, if it's too much of a pain, I'll follow your lead on that one and use it in the basement as a stereo.
Thanks,
Pat
Gotta love the internet.
BigTom, I've got the identical symptoms that you describe with my AVR5. I'd love it if you could shoot me any useful pics/docs that you have on the topic. I've opened it up, but I don't see anything amiss. Everything, down to the mute button, is the same as you describe it.
Although I'd like to fix the channel rather than reroute it, if it's too much of a pain, I'll follow your lead on that one and use it in the basement as a stereo.
Thanks,
Pat
Pat,
I have the entire service manual at work I can send you, it's 27meg PDF file though if I recall correctly so we'll have to figure out some way to send it to you. First things first, you might as well measure the emiter resisters and also the 2SA1695 & 2SC4468 to check for any shorts. Now that I know where they are it's pretty easy to get a DMM in there and check especially if you've got everything apart and pulled out the heatsink with amp board attached.
Anyways, keep in touch and we'll try to get yours back up and running! I'm still enjoying mine in the office, get alot of compliments on it to from envious coworkers
I have the entire service manual at work I can send you, it's 27meg PDF file though if I recall correctly so we'll have to figure out some way to send it to you. First things first, you might as well measure the emiter resisters and also the 2SA1695 & 2SC4468 to check for any shorts. Now that I know where they are it's pretty easy to get a DMM in there and check especially if you've got everything apart and pulled out the heatsink with amp board attached.
Anyways, keep in touch and we'll try to get yours back up and running! I'm still enjoying mine in the office, get alot of compliments on it to from envious coworkers
That'd be great...
I could set up an FTP server for you to drop it on or pick it up from anywhere you'd like to drop it... also, if you have skype, we could do a transfer that way-- it's generally pretty fast.
Unfortunately, I don't know my way around this board... I'm guessing that the emitter resistors are those five large white, 3-pin jobs towards the front?... given your description of the amps as being carbon copies, their proximity to power xsisters, etc... they seem like the likely culprits. Still, you mentioned that someone peeked in there and saw the problem with yours? I don't see anything obvious; I'd expected a cap to have splattered somewhere or something to have had it just fail like this.
I'm really not much of a hifi tech, just a recovering electrical engineer (on the wagon almost 10 years) hoping to avoid throwing what seems like a perfectly servicable unit into the waste stream.
Your help's appreciated.
Pat
I could set up an FTP server for you to drop it on or pick it up from anywhere you'd like to drop it... also, if you have skype, we could do a transfer that way-- it's generally pretty fast.
Unfortunately, I don't know my way around this board... I'm guessing that the emitter resistors are those five large white, 3-pin jobs towards the front?... given your description of the amps as being carbon copies, their proximity to power xsisters, etc... they seem like the likely culprits. Still, you mentioned that someone peeked in there and saw the problem with yours? I don't see anything obvious; I'd expected a cap to have splattered somewhere or something to have had it just fail like this.
I'm really not much of a hifi tech, just a recovering electrical engineer (on the wagon almost 10 years) hoping to avoid throwing what seems like a perfectly servicable unit into the waste stream.
Your help's appreciated.
Pat
I was the fellow helping Tom look at this amp.
We found one of the emitter resistors had just the finest hairline crack through it, so look for those, they are the five big white three pin blocks like you had pointed out. Once we took the resistor out, it fell into peices.
Also do a meter check on the output transistors and the driver transistors. The output transistors are on the heatsink and the driver transistors will be very near by. For a NPN transistor, turn your meter to diode check, put the positive lead on the base and touch the collector and the emitter. You should have a diode drop on both of these. Your meter should stay on overload for the rest of the combinations (Like negative on base and touch the collector and emitter, you should get overload). This will be a good transistor based on your meter check. Its opposite for PNP.
There may also be some small resistors in the area of the output transistors that are darkened or blackened.
Hope some of this helps.
We found one of the emitter resistors had just the finest hairline crack through it, so look for those, they are the five big white three pin blocks like you had pointed out. Once we took the resistor out, it fell into peices.
Also do a meter check on the output transistors and the driver transistors. The output transistors are on the heatsink and the driver transistors will be very near by. For a NPN transistor, turn your meter to diode check, put the positive lead on the base and touch the collector and the emitter. You should have a diode drop on both of these. Your meter should stay on overload for the rest of the combinations (Like negative on base and touch the collector and emitter, you should get overload). This will be a good transistor based on your meter check. Its opposite for PNP.
There may also be some small resistors in the area of the output transistors that are darkened or blackened.
Hope some of this helps.
Pat,
If you get an FTP setup let me know and I'll try to connect and upload the file to you. I'm not sure if my work will allow those types of connection (damn IT group) but we can try anyways. Send me the relative connection info to bigtom209@hotmail.com
Another very quick way to check the output transistors especially if you're having troubles seeing which are the base/emiter/collector etc is just set your meter to ohms and go pin to pin. If you have shorts... not a good sign. On my 2SA1695 every pin to every pin read a short, so I pulled the leads off to remove it from the circuit and retested it just to make sure and yep, everything still shorted so that device even though looked fine was crap. Took a whopping 20 seconds to find that problem once I actually knew where to look
*EDIT* While I'm thinking about it, if you're serious about getting this amp fixed and if you find 1 or 2 channels blown and are in need of the emiter resistors I was able to get HMR to send me 5 of those emiter resistors which are a bit of a PITA to find, maybe we could work together if you order some of the output transistors grab an extra set for me and I can send you a few of the emiter resistors! We can work out some form of swapping of parts to hopefully get both running! I know I could get mine running 100% again if I could get those transistors, the cost on them is cheap but the shipping/handling/duty charges I pay to get them to me makes the price go up a fair bit, $10 in parts could end up being $40+ to my door, so for an old reciever it's not worth it to me. If you had an extra set you could chuck in an envelope and mail it to me for $1 and me the same with the resistors...
If you get an FTP setup let me know and I'll try to connect and upload the file to you. I'm not sure if my work will allow those types of connection (damn IT group) but we can try anyways. Send me the relative connection info to bigtom209@hotmail.com
Another very quick way to check the output transistors especially if you're having troubles seeing which are the base/emiter/collector etc is just set your meter to ohms and go pin to pin. If you have shorts... not a good sign. On my 2SA1695 every pin to every pin read a short, so I pulled the leads off to remove it from the circuit and retested it just to make sure and yep, everything still shorted so that device even though looked fine was crap. Took a whopping 20 seconds to find that problem once I actually knew where to look
*EDIT* While I'm thinking about it, if you're serious about getting this amp fixed and if you find 1 or 2 channels blown and are in need of the emiter resistors I was able to get HMR to send me 5 of those emiter resistors which are a bit of a PITA to find, maybe we could work together if you order some of the output transistors grab an extra set for me and I can send you a few of the emiter resistors! We can work out some form of swapping of parts to hopefully get both running! I know I could get mine running 100% again if I could get those transistors, the cost on them is cheap but the shipping/handling/duty charges I pay to get them to me makes the price go up a fair bit, $10 in parts could end up being $40+ to my door, so for an old reciever it's not worth it to me. If you had an extra set you could chuck in an envelope and mail it to me for $1 and me the same with the resistors...
It's a deal...
As soon as I have a chance, I'm going to look at those things. And yeah, I'm happy to do a parts swap if necessary (which, it sounds like it will be). I'd be happy to get this thing going again, though, I've got my eye on this Onkyo rig that gets great reviews...
We'll call this an excuse to upgrade. I think the AVR5 may become the driving force behind mad inter-house sound experiments if it's revived.
Pat
As soon as I have a chance, I'm going to look at those things. And yeah, I'm happy to do a parts swap if necessary (which, it sounds like it will be). I'd be happy to get this thing going again, though, I've got my eye on this Onkyo rig that gets great reviews...
We'll call this an excuse to upgrade. I think the AVR5 may become the driving force behind mad inter-house sound experiments if it's revived.
Pat
2SA1695 Shot
Yep... that transistor in the center of the amps is shot (and visibly burnt). The resistors look OK as far as I can tell (no cracks or burns). So, I'm just going to order one to replace this. Let me know how many you'd like, and I'll get a few and mail them to you. They're all of $1.75US each, but I think I'll just get a spare and only fix the one that fried. I'm concerned that I'll do more damage pulling out the others for preventative replacement.
Yep... that transistor in the center of the amps is shot (and visibly burnt). The resistors look OK as far as I can tell (no cracks or burns). So, I'm just going to order one to replace this. Let me know how many you'd like, and I'll get a few and mail them to you. They're all of $1.75US each, but I think I'll just get a spare and only fix the one that fried. I'm concerned that I'll do more damage pulling out the others for preventative replacement.
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