HK330A Doesn't Want To Do Stereo

DreadPirate · 7th May 2006, 09:28 PM

This H/K receiver is acting funny FM-wise. The signal strength meter is dead in FM, but only in FM, it works fine in AM. In addition, channels come in fine in FM mono and when you switch to FM stereo, the signal still comes in on mono (no stereo) and I have a good antenna. The FM beacon glows dimly and continuously when the unit is on and in all modes The schematic can be found here:

http://www.eserviceinfo.com/download...rdon_330A.html

Scroll down a bit for the link just under the "Download Restrictions" box.

Using a good viewer like Brava, the schematic is readable, I have found other viewers are finicky with .TIF files.

The only measurement I have made so far is at the stereo/mono switch, I get 104K Ohm in stereo and 0 Ohm in mono.

Any comments appreciated.

latala · 10th May 2006, 03:48 PM

The hk 330A uses a discrete switched envelope decoder that is not mono /stereo compatable. Hence you will get no output on stereo if the 38 khz carrier is not being generated.
Do you have a scope?
If so trace the pilot 19 khz tone and then through the frequency doubler to 38 khz
First suspect the freq doubler transistor
I have had these fail in the past
regards Trev

DreadPirate · 10th May 2006, 06:50 PM

Thanks trev. No I do not have a scope. Which transistor is the frequency doubler?

DreadPirate · 10th May 2006, 07:24 PM

This might help, Replacement Parts List:

http://img128.imageshack.us/img128/6...rtslist0km.jpg

latala · 10th May 2006, 09:06 PM

Shame about the scope! can you not loan one as its difficult without
The transistor you are looking for is tr303 a 2sa49
however any general purpose small signal PNP transistor should work
regards Trev

7th May 2006, 09:28 PM	#1
DreadPirate diyAudio Member Join Date: Jan 2006 Location: Northern Virginia, USA	HK330A Doesn't Want To Do Stereo This H/K receiver is acting funny FM-wise. The signal strength meter is dead in FM, but only in FM, it works fine in AM. In addition, channels come in fine in FM mono and when you switch to FM stereo, the signal still comes in on mono (no stereo) and I have a good antenna. The FM beacon glows dimly and continuously when the unit is on and in all modes The schematic can be found here: http://www.eserviceinfo.com/download...rdon_330A.html Scroll down a bit for the link just under the "Download Restrictions" box. Using a good viewer like Brava, the schematic is readable, I have found other viewers are finicky with .TIF files. The only measurement I have made so far is at the stereo/mono switch, I get 104K Ohm in stereo and 0 Ohm in mono. Any comments appreciated.

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10th May 2006, 03:48 PM	#2
latala diyAudio Member Join Date: Feb 2006 Location: staffordshire	The hk 330A uses a discrete switched envelope decoder that is not mono /stereo compatable. Hence you will get no output on stereo if the 38 khz carrier is not being generated. Do you have a scope? If so trace the pilot 19 khz tone and then through the frequency doubler to 38 khz First suspect the freq doubler transistor I have had these fail in the past regards Trev

10th May 2006, 06:50 PM	#3
DreadPirate diyAudio Member Join Date: Jan 2006 Location: Northern Virginia, USA	Thanks trev. No I do not have a scope. Which transistor is the frequency doubler?

10th May 2006, 07:24 PM	#4
DreadPirate diyAudio Member Join Date: Jan 2006 Location: Northern Virginia, USA	This might help, Replacement Parts List: http://img128.imageshack.us/img128/6...rtslist0km.jpg

10th May 2006, 09:06 PM	#5
latala diyAudio Member Join Date: Feb 2006 Location: staffordshire	Shame about the scope! can you not loan one as its difficult without The transistor you are looking for is tr303 a 2sa49 however any general purpose small signal PNP transistor should work regards Trev

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