hey guys.
i've just got a harman kardon avr335 recently for free,
free because the two PCB's on the side of the transformer were snapped however i've repaired these and the unit now turns on (with proper voltages on both boards).
problem is there is no sound, nor can i get any signal out of the RCA pre-outs on the back.
i've tried coax and rca inputs on all of the ports to get no signal.
i've also taken the whole unit apart and put it back together finding no visible faults. i dont think theres any use in measuring the bias' yet?
i _think_ its a problem between the "input" and the "output \ transistor stage" boards, in which the input board is directly above the other. has anyone ever had any experiance in repairing these sorts of problems?
fairly sure that theres no "mute" on. can hear a slight crackle if you disconnect or connect speakers while the unit is turned on.
sorry if i've posted in the wrong forum and\or wasted your time
thanks!
i've just got a harman kardon avr335 recently for free,
free because the two PCB's on the side of the transformer were snapped however i've repaired these and the unit now turns on (with proper voltages on both boards).
problem is there is no sound, nor can i get any signal out of the RCA pre-outs on the back.
i've tried coax and rca inputs on all of the ports to get no signal.
i've also taken the whole unit apart and put it back together finding no visible faults. i dont think theres any use in measuring the bias' yet?
i _think_ its a problem between the "input" and the "output \ transistor stage" boards, in which the input board is directly above the other. has anyone ever had any experiance in repairing these sorts of problems?
fairly sure that theres no "mute" on. can hear a slight crackle if you disconnect or connect speakers while the unit is turned on.
sorry if i've posted in the wrong forum and\or wasted your time
thanks!
Download the AVR diagnosis doc:
http://www.eserviceinfo.com/downloadsm/29162/Harman/Kardon_AVR (all).html
It includes the AVR330, the model previous to the 335, it should be similar enough.
AVR135 Service Manual:
http://www.eserviceinfo.com/downloadsm/18040/harman kardon_AVR 135.html
The 235 and 335 are similar as well, however I only have a service manual for the 340. I can email this to you if you want, it is quite large (13mb).
You may want to check fusible resistors supplying the lower voltage rails, they'll be attached to the main transformer, before any bridges. I recently repaired a similar age AVR(135?) receiver and two fusible resistors went out due to a ceramic capacitor that shorted mysteriously. However the resistors are designed such that they do not burn externally and were only found after testing with a dmm.
http://www.eserviceinfo.com/downloadsm/29162/Harman/Kardon_AVR (all).html
It includes the AVR330, the model previous to the 335, it should be similar enough.
AVR135 Service Manual:
http://www.eserviceinfo.com/downloadsm/18040/harman kardon_AVR 135.html
The 235 and 335 are similar as well, however I only have a service manual for the 340. I can email this to you if you want, it is quite large (13mb).
You may want to check fusible resistors supplying the lower voltage rails, they'll be attached to the main transformer, before any bridges. I recently repaired a similar age AVR(135?) receiver and two fusible resistors went out due to a ceramic capacitor that shorted mysteriously. However the resistors are designed such that they do not burn externally and were only found after testing with a dmm.
ahhh.
Thanks for your help!
I've found two (out of 4) dead fusible resistors, all of which are 0.47 ohms and 1 watt. I've now rung around and I can't find anywhere local that sells any sort of fusible resistors, nor a 0.47ohm resistor.
I'm assuming that when they blow they are designed to do this without exploding\catching fire etc, but for testing purposes my choices are:
option 1:
using 2, 1ohm resistors (1 watt) in parallel , to bring them down to ~0.5ohms, however I think that this will let too much current through before blowing and I could end up with more expensive components damaged,
option 2:
use 4 1.8ohm, 1/4watt resistors in parallel which is approx 0.45ohms, and I think this may add up to 1 full watt like the original specifications.
I think option two would be the way to go?
If it catches fire, it catches fire
Thanks for your help!
I've found two (out of 4) dead fusible resistors, all of which are 0.47 ohms and 1 watt. I've now rung around and I can't find anywhere local that sells any sort of fusible resistors, nor a 0.47ohm resistor.
I'm assuming that when they blow they are designed to do this without exploding\catching fire etc, but for testing purposes my choices are:
option 1:
using 2, 1ohm resistors (1 watt) in parallel , to bring them down to ~0.5ohms, however I think that this will let too much current through before blowing and I could end up with more expensive components damaged,
option 2:
use 4 1.8ohm, 1/4watt resistors in parallel which is approx 0.45ohms, and I think this may add up to 1 full watt like the original specifications.
I think option two would be the way to go?
If it catches fire, it catches fire
Wattage/exact resistance doesn't really matter, I replaced mine with 1.5R/2W flameproof. If the old ones blew, then something is very likely shorted. Testing will only consist of connecting resistors temporarily and using a dmm to determine the current through them while the receiver is powered on very briefly, maybe a second (not enough time for your resistors to overheat and blow). After you've measured the current, you can determine if something is shorted and begin searching for what has gone bad. Once you find out what's shorted, then worry about sourcing resistors; can't say I know of any suppliers over there, you may have to do some searching.
Also, you can just replace the fusible with flameproof. Different name, same function. Flameproofs are quite often used in TVs, especially in projector TV convergence circuits. May want to try some friendly TV shops or something.
Also, you can just replace the fusible with flameproof. Different name, same function. Flameproofs are quite often used in TVs, especially in projector TV convergence circuits. May want to try some friendly TV shops or something.
Hi guys! I found this post just googling, maybe you can give me a hand. I have a harman kardon avr 340 with no sound. Everything seems ok, the receiver turns on, recognizes different types of entries, but no sound, neither by headphone nor the pre-out. Do you think that can be something in the board attached to the transform?
By the way...I know nothing about electronic, buy your answer may help me to guide a friend of mine who have some electronic habilities.
Thanks in advance, Federico.
By the way...I know nothing about electronic, buy your answer may help me to guide a friend of mine who have some electronic habilities.
Thanks in advance, Federico.
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