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-   -   Harman Kardon AVR 270 (https://www.badcaps.net/forum/showthread.php?t=76451)

playman 05-05-2019 04:11 PM

Harman Kardon AVR 270
 
I have a HK AVR 270 and only Zone 2 works on it.
Any one know on what PCB the Zones are located in the amp, and maybe by any chance know what might have broken?

Link to the service manual
https://elektrotanya.com/harman_kard.../download.html

madan1 05-05-2019 05:02 PM

Re: Harman Kardon AVR 270
 
Do the headphones work for Z1?

Also, have you tried to reset the unit?


p.s. Check SM page 162
If you are able to pass every source ( analog and digital ) through the zone2/pre-out output, than everything on the "smart" side works fine ( great news ).

playman 05-07-2019 01:01 PM

Re: Harman Kardon AVR 270
 
Quote:

Originally Posted by madan1 (Post 895025)
Do the headphones work for Z1?

Also, have you tried to reset the unit?


p.s. Check SM page 162
If you are able to pass every source ( analog and digital ) through the zone2/pre-out output, than everything on the "smart" side works fine ( great news ).

I'm waiting on my replacements parts for the SMPS board, will check that soon as I've replaced them.

playman 05-07-2019 02:50 PM

Re: Harman Kardon AVR 270
 
1 Attachment(s)
I was taking a better look at the CUP12457 board and noticed a smudge on it.
tested the Q2107 and belive it's broken, in the manual it's marked as
RT1P144C(PNP,SC-59,SISAHAYA
found the datasheet
https://pdf1.alldatasheet.com/datash.../RT1P144C.html
I can't find it for sale on either Mouser or farnell, any one know a suitable replacement for it?

madan1 05-07-2019 03:17 PM

Re: Harman Kardon AVR 270
 
https://www.aliexpress.com/item/50pc...884439063.html

playman 05-08-2019 01:22 PM

Re: Harman Kardon AVR 270
 
Thanks for that madan1 unfortunately I cant order it from aliexpress or alibaba as for some reason they started declining my card and i just spent almost 2 hours talking to their assistance witch got me nowhere, amazon ebay/paypal even google have no trouble with accepting my card.

Is there any other site or suitable replacement available.

R_J 05-08-2019 05:55 PM

Re: Harman Kardon AVR 270
 
A DTA114, should be the same, digikey DTA114EKAT146CT-ND What do you mean by broken? It will be hard to test with a meter due to the internal resistance, I doubt it is the cause of the problem

playman 05-09-2019 09:41 AM

Re: Harman Kardon AVR 270
 
Quote:

Originally Posted by R_J (Post 895585)
A DTA114, should be the same, digikey DTA114EKAT146CT-ND What do you mean by broken? It will be hard to test with a meter due to the internal resistance, I doubt it is the cause of the problem

Thanks for that, I noticed that R1 and R2 have the resistance of 10k in the DTA114, but the RT1P44 has the resistance of R1 10k and R2 47k, is that ok?

I thought it was broken because the Diode function on my meter gave me no readings and
Positive probe on collector gave me a reading of 6.05M ohm on both Base and emitter
Positive probe on Emitter gave me reading of 60k ohm on Base, same result with positive probe on Base.
And I managed somehow to break one of the leads :/ on the other one.

R_J 05-09-2019 09:56 AM

Re: Harman Kardon AVR 270
 
All similar https://www.digikey.com/products/en/...pre-biased/292

This should be better SMUN2114T1GOSCT-ND https://www.digikey.com/product-deta...SCT-ND/9087746

playman 05-09-2019 10:47 AM

Re: Harman Kardon AVR 270
 
Quote:

Originally Posted by R_J (Post 895677)

Thank you so much for that, putting in an order now.

P.S.
Did my readings say if it was bad or ok?

R_J 05-09-2019 11:22 AM

Re: Harman Kardon AVR 270
 
it is what is refered to as a digital transistor
Positive probe on collector gave me a reading of 6.05M ohm on both Base and emitter
This is what it should read (e-c, b-c open)
Positive probe on Emitter gave me reading of 60k ohm on Base, same result with positive probe on Base
47k +10k = 57k (very close to 60k which is correct
I would say it was good

playman 05-09-2019 11:25 AM

Re: Harman Kardon AVR 270
 
Quote:

Originally Posted by R_J (Post 895697)
it is what is refered to as a digital transistor
Positive probe on collector gave me a reading of 6.05M ohm on both Base and emitter
This is what it should read (e-c, b-c open)
Positive probe on Emitter gave me reading of 60k ohm on Base, same result with positive probe on Base
47k +10k = 57k (very close to 60k which is correct
I would say it was good

Allright thanks again :D

playman 05-15-2019 05:25 PM

Re: Harman Kardon AVR 270 - No power
 
4 Attachment(s)
I received the parts today and soldered them in.
Now it still won't power on, just like it did before I took it apart.
The orange power light turns white for a second then returns to orange.
I can hear a faint noise coming from the SMPS PCB, like it's trying to start but can't.
The noise seems to be coming from those two big black transformers or near them.
The Ceramic caps C984 and C983 were really dark so I replaced them, saw it somewhere that if those caps are gone the AVR would have the same symptom as I had/have.

Any one know what might be wrong?

R_J 05-15-2019 07:04 PM

Re: Harman Kardon AVR 270
 
You seem to be making it worse, In post one the zone 2 was working and your fault was with zone 1, and now nothing is working correct?
If the amp was working with zone 2, why would you change parts in the power supply? this makes no sense.

Did you just change the two 471/1kv caps in the power supply so far?

R_J 05-15-2019 08:38 PM

Re: Harman Kardon AVR 270
 
I think you have a short somewhere in the output section, with the amp off, check the resistance between +vcc and ground and -vcc and ground. If you don't have any shorts, Monitor the voltage on +vcc and then -vcc when you turn on the amp and see if you get +/- 50 volts
Did you have speakers connected to zone2 L&R and they were working?

playman 05-16-2019 10:55 AM

Re: Harman Kardon AVR 270
 
Quote:

Originally Posted by R_J (Post 896637)
You seem to be making it worse, In post one the zone 2 was working and your fault was with zone 1, and now nothing is working correct?
If the amp was working with zone 2, why would you change parts in the power supply? this makes no sense.

Did you just change the two 471/1kv caps in the power supply so far?

Hi, sorry, I guess I wasn't clear enough in my post, my bad.
The problem started at first with the zone problem, when I was checking it's settings out, it went to standby mode suddenly with a slight heat smell, after that it did not want to turn on again.
I was so sure that these caps were the problem since they looked burned, so I just asked about the zone problem here.
If I remember right, I heard some low crackling noises as I connected the speaker, just like it usually happens when you connect a speaker.
When I was putting it to gather I noticed that some of the large transistors on the large heatsink had been changed, and the repairman seems to have a little brute on the heatsink fan connector, as
the two pins were trough the PCB and ripped the connections under it, But I believe I've managed to repair it. The fan connection is located on the sound output board.

Yes I only changed the two 471/1kv caps.

I checked the VCC-/+ on the SMPS PCB the resistance started from 0.5k Ohm or so and just raised on both +and -, as if the DMM was charging it, stopped measuring at 2k Ohm
When I switched the Unit on the volts seemed to reach 50-55V + and -, just for a part of a second.

R_J 05-16-2019 11:16 AM

Re: Harman Kardon AVR 270
 
Your power supply is working ok, I suspect there is a fault in one of the amp output sections. place your meter probes on each speaker output terminal and turn on the amp, you should see 0 volts, if you see more than a couple volts on any of the speaker output terminals, that section has a fault, you will likely need to power of the amp between each speaker test as the amp will shut down.

playman 05-16-2019 04:35 PM

Re: Harman Kardon AVR 270
 
Quote:

Originally Posted by R_J (Post 896752)
Your power supply is working ok, I suspect there is a fault in one of the amp output sections. place your meter probes on each speaker output terminal and turn on the amp, you should see 0 volts, if you see more than a couple volts on any of the speaker output terminals, that section has a fault, you will likely need to power of the amp between each speaker test as the amp will shut down.

Just tested them, Front Right output gives me a reading of -22v (negative).
All the other outputs gave a reading of 0.5v or so.

R_J 05-16-2019 04:56 PM

Re: Harman Kardon AVR 270
 
Ok. you now know where the problem is, start by checking the 4, 0.47Ω ceramic resistors, then check the output transistors in the FR amp circuit. Also check the two 18Ω R631 & R636 resistors, You can compare your readings with one of the working channels if something looks off

playman 05-16-2019 05:43 PM

Re: Harman Kardon AVR 270
 
Quote:

Originally Posted by R_J (Post 896809)
Ok. you now know where the problem is, start by checking the 4, 0.47Ω ceramic resistors, then check the output transistors in the FR amp circuit. Also check the two 18Ω R631 & R636 resistors, You can compare your readings with one of the working channels if something looks off

R631 & R636? Don't you mean R632 & R637?
R631 & R636 are from the Center channel.
Any way those 4 18 Ohm are ok
R723 & R725 are open
Going to test the Trans now.

R_J 05-16-2019 05:57 PM

Re: Harman Kardon AVR 270
 
Yes, I scrolled up too far to the Center channel
If R723/725 are open transistor could be bad, also check the base resistors, R647/652, then work back checking the driver transistors and resistors. comparing same components to a working channel is helpfull sometimes

playman 05-16-2019 07:08 PM

Re: Harman Kardon AVR 270
 
My DCA55 says that there is a short between Collector and Emitter on Q652 trans.
The other two seem to be ok.
Will be testing rest of the stuff tomorrow.

playman 05-17-2019 06:54 PM

Re: Harman Kardon AVR 270
 
Just finished testing all the components in that channel.
Nothing out of the ordinary as I could notice, except for one Diode.
D582 measured 400kΩ and rising when positive probe was on cathode, other Diodes
did not do that, trans Q652 and the two resistors R723 and R725 are not installed.
Q882 and Q871 seemed ok.
I did not check the To-92 Transistors though.
Capacitors measured fine with the ESR meter, did not check the ceramic ones though.

R_J 05-17-2019 07:39 PM

Re: Harman Kardon AVR 270
 
You could lift one end of D582 to check it, Check the transistors like Q562, Q502, maybe they have some leakage.

playman 05-21-2019 10:25 AM

Re: Harman Kardon AVR 270
 
Quote:

Originally Posted by R_J (Post 896977)
You could lift one end of D582 to check it, Check the transistors like Q562, Q502, maybe they have some leakage.

D582 Looks ok.
Q562, Q502 looked ok also, I also checked the other remaining 6 and they also looked ok.

So I guess there is nothing left but to order the Q652 trans and the 0.47Ω resistors, plug them in and turn on the amp?

playman 06-04-2019 09:14 AM

Re: Harman Kardon AVR 270
 
I finally received my resistors today.
I decided to measure them just in case, They measured around 0.6Ω
they were supposed to be 0.47Ω.
Unfortunately my DMM only measures from 0.1Ω and up-to 60mΩ.
(not showing the extra decimal)

Is it ok for me to use them or should I order a new ones from some one else?

Ps
Is there any good way to know if they are M-Oxide films or just plain Carbon/metal film resistors?

R_J 06-04-2019 11:56 AM

Re: Harman Kardon AVR 270
 
The resistors are very low resistance so when you measured them you need to add your lead resistance, short your meter leads together, I bet the reading is ~.2Ω
What type of resistor did you order? I would'nt be too concerned, either type will work
Just a note:
Quote:

Unfortunately my DMM only measures from 0.1Ω and up-to 60mΩ.
mΩ usually refers to milli ohm, MΩ for meg ohm

playman 06-04-2019 12:53 PM

Re: Harman Kardon AVR 270
 
When I short it I get 0.1Ω reading
I bought this item.
https://www.ebay.co.uk/itm/30Pcs-2W-...frcectupt=true

sorry for that, I keep forgetting to capitalize letters when it is needed.

So I'll just plug them in and test the amp then.

playman 06-04-2019 03:23 PM

Re: Harman Kardon AVR 270
 
I've finished putting it to gather and all seems to work, I did reset it just in case.
Was able to listen to music on zone 1 with two speakers.
Now I just have to put it into the living room to test the 5.1 setup.
I did notice that the fans never turned on, even after running the amp on high volume for few minutes, did notice the heat sink getting hot, but not crazy hot.
Is there any way to test if the fans are working, besides taking them out and hooking them to another power source.

R_J 06-04-2019 03:51 PM

Re: Harman Kardon AVR 270
 
This is from the manual: It is normal for the fan to remain off at most normal volume levels.
I would think it will cut in after its been on for a while and runing at a high output.

playman 06-04-2019 03:58 PM

Re: Harman Kardon AVR 270
 
Quote:

Originally Posted by R_J (Post 899694)
This is from the manual: It is normal for the fan to remain off at most normal volume levels.
I would think it will cut in after its been on for a while and runing at a high output.

I read that also in the manual, just thought that they would turn on at that heat.
The amp should go into protect mode soon as it gets to hot right?

R_J 06-04-2019 04:05 PM

Re: Harman Kardon AVR 270
 
There are two test points you can short CN11 (FAN TEST) (page 170 of manual)

playman 06-04-2019 04:17 PM

Re: Harman Kardon AVR 270
 
The fans atleast work, guess there's nothing left but to place it into it's future home.

Thank you so much for your time and all the help, it's really appreciated!!.

playman 06-07-2019 04:41 PM

Re: Harman Kardon AVR 270
 
Update!
I connected everything last night and it ran just fine, except it was really hot, I barely could
hold my hand on top of the AVR and smelled heat/burning smell of it and noticed that neither of the fans were running.
So I quickly jumped for my table fan and cooled it down and had no trouble after that.
Until today....
I bought new HDMI cables and was starting to change things out and do cable management when the front right
channel started jumping in and out, like it was a bad cable/connection.
put another speaker on that channel with a new wire and it continued jumping in and out.
HDMI 1 is jumping in and out also.
When I turn it off it will turn on again x time later, if I turn it of then it will stay off.

Any idea what's wrong now?

R_J 06-07-2019 07:39 PM

Re: Harman Kardon AVR 270
 
Sounds like you still have a problem with the F.R. channel, maybe a poor solder connection somwhere if it does work but is intermitint. Did you check the voltage on the F.R. speaker after you repaired the channel? it should be close to 0 like the others.
If the amp turns on and off by itself when the hdmi cable is connected, it could be a poor connection on the hdmi plug on the board.
Check the voltage on D970 (k) and D980 (k), they should be logic high to turn on the fans, also check if the temp sensing ic (ic10) is connected

playman 06-08-2019 12:43 PM

Re: Harman Kardon AVR 270
 
Quote:

Originally Posted by R_J (Post 900142)
Sounds like you still have a problem with the F.R. channel, maybe a poor solder connection somwhere if it does work but is intermitint. Did you check the voltage on the F.R. speaker after you repaired the channel? it should be close to 0 like the others.

FR channel seems completely dead now, no sound coming from it.
Did check it's voltage right after the repair and it was similar to the other channels.
Did not notice any bad solder points in that channel, but could try and re-solder the channel.
The FR channel worked just fine it's first evening, it was not until they day after it started acting up.

My measurements on all channels
FR -1.5mv
FL 2.0mv
FHR -7.5mv
FHL -7.5
RR 0.4mv
RL -4.0mv
C -7.5mv

Quote:

Originally Posted by R_J (Post 900142)
If the amp turns on and off by itself when the hdmi cable is connected, it could be a poor connection on the hdmi plug on the board.

It has never turned off by itself, only turned on by itself, after few hours (didint time it)
Unplugged all the HDMI's today before I went out and when I came back home 1 or 2 hours later it was still off.
I was only using the HDMI 2-3-4 and 5 HDMI 1 was not connected when it turned itself on.
I had PS4 (off) Chromecast (On) Micro PC with Kodi installed (On) and the TV box (on) connected to it, not sure if any of them might have sent a signal to the AVR to turn on, or if the AVR allows to be woken up trough HDMI.

Quote:

Originally Posted by R_J (Post 900142)
Check the voltage on D970 (k) and D980 (k), they should be logic high to turn on the fans, also check if the temp sensing ic (ic10) is connected

D980 & D970 gave me 13.4mv (just probed it's left and right side, did not measure from the body, that's correct?)
The IC10 is connected, it's the one on the heatsink right?

Why do the AVR always have to be so hard to work on? lol

playman 06-11-2019 11:43 AM

Re: Harman Kardon AVR 270
 
I've resoldered the FR Channel and everything seems to be alright.
Did also drag the solder tip over the HDM1 contacts and haven't noticed any problem with it.
Would it be ok to short the fan test pins so the fans would just stay on, or would I have to fix some PC fan to the AVR instead?

R_J 06-11-2019 11:59 AM

Re: Harman Kardon AVR 270
 
Did you check the bias after repairing the FL channel? page 75 of manual
Have you check the voltage on the temp ic? BN10 should have +5 (3) gnd (2) and temp output voltage on (1) Check the output voltage then heat the ic with a heat gun a bit and see if the voltage changes
D970 would have a logic high to turn on the fan. I can't see that the amp should get that hot a low volume.
This amp has 2 fans correct?

playman 06-12-2019 10:09 AM

Re: Harman Kardon AVR 270
 
Did not check the bias, but have now and tuned them all to 25mv.
Pin 1 gave me 5.17v and did not change with the heating.
Pin 2 gave me 3v and raised as I heated it, I belive the amp went into protect mode as it raised over 4v. Could have been coincidence.
Yes the amp has one on the heatsink and 1 in the back.

playman 06-12-2019 10:14 AM

Re: Harman Kardon AVR 270
 
Did not check the bias, but have now and tuned them all to 25mv.
Pin 1 gave me 5.17v and did not change with the heating.
Pin 2 gave me 3v and raised as I heated it, I belive the amp went into protect mode as it raised over 4v. Could have been coincidence.
Yes the amp has one on the heatsink and 1 in the back.

EDIT:
checked now two times with the sensor loose from the heatsink and the amp turns off when I heat the sensor, but the fans never turn on though.


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