Re: Harmon Karden AVR 146 Won't stay powered
I was incorrect on the resistance, it was 160000. Anyway, thainks to everyone, especially BUDM. Indeed, it was the thermal fuse that was buried inside the transformer. I checked all the diodes, resistance on the boards connected to the transformer to verify there was no short. I took the suggestion about how to solder a thermal fuse without overheating it, plugged it in and BAMM. It is now workig!!
I could not have done this without all of the support so I thaink each and everyone of you!!!
Bslodk
Member
Last Activity: 07-23-2014, 09:18 PM
Joined: 06-18-2014
Location: St. Louis
-
Re: Harmon Karden AVR 146 Won't stay powered
Wow, you guys are fantastic!! I was about to give up until you provided another thread of a similar transformer. I started chipping away at the plastic this morning. After doing some probing, digging, etc., there it was and it is definately OPEN.
I was concerned I might have damaged the wiring, but when bypassing the thermal fuse I am getting 1.6k of resistance so I feel confident I will be ok. The next question is do I need to rewrap the windings in any kind of tape to protect them after replacing the...Leave a comment:
-
Re: Harmon Karden AVR 146 Won't stay powered
Ok, guys. Here are the pics. I pulled off all the tape that I could without wanting to cause damage to the windings. Are you possible saying that I need to break off part of the plastic to gain access to the thermal fuse?
Sorry for the confusion, I am just trying to follow the steps I am told. Once again, I appreciate the help in advance.
...
Leave a comment:
-
Re: Harmon Karden AVR 146 Won't stay powered
Ok guys, I have torn into the transformer as best I can peeling away the tape and I find NO thermal fuse, believe me, I wanted to find one. So, I have checked for voltage at CN91 and I have 120 VAC when the relay kicks in. Additionally, I probed the wires to ensure there was not a break in the leads to transformer, but find nothing. No voltage at any of the posts.
The next question, where do I find a transformer for this beast considering there is no rating or schematic drawings on the output voltage for the transformer?...Leave a comment:
-
Re: Harmon Karden AVR 146 Won't stay powered
Ok, thank you for the clarification on the the thermal fuse. I will start peeling back the insulation and look for a thermal fuse and check the connectivity points on the transformer. will post what I find.
Understood about the output posts, too, if I find a thermal fuse blown.Leave a comment:
-
Re: Harmon Karden AVR 146 Won't stay powered
Disconnecting the wires at CN91 and checking resistance on the wires to the transformer I get NOTHING! No resistance so I assume this means the transformer is indeed shot, right?
I did not check the resistors eariler and they checked out. I have not checked the caps in your highlighted diagram because at this point I am not getting resistance on the wires and secondly, I did not want to start unsoldering the caps if it looks like the transformer is indeed bad.
Do we agree that it looks like it is indeed the...Leave a comment:
-
Re: Harmon Karden AVR 146 Won't stay powered
Guys,
I am beginning to suspect a bad transformer. I cannot tell what type of A/C voltage I should be getting out of the posts at the transformer, but all are less than 1VAC. There is a slight vibration coming from the transformer (like a bad connection of some sort internally), but not a hum. Additionally, when I check voltages for DC at the rectifiers on D991 and D992 I get nothing. Presently, the transformer is completely disconnected from the chassis with the exception of only the 120 VAC power supplying the transformer....Leave a comment:
-
Re: Harmon Karden AVR 146 Won't stay powered
Thank you for the clarification. I start this weekend on tracing. I appreciate the guidance.Leave a comment:
-
Re: Harmon Karden AVR 146 Won't stay powered
I know I am showing my ignorance here, but where do I check for the main supply voltages? I am attaching the entire schematic, but I do not see anywhere on the schematic where it shows I can see the direct output voltages from the transformer. What I have primarily been looking at is page 170.
I do find all of the plugs and the boards. Looking at the connector on 11916-4 (9 pin connector) the nomenclature is confusing to me. pin 1 +5vd pin 2 17v, etc. what is +5VD? Does that mean +5 dc volts? and pin 8, 5.6VC. What is...Leave a comment:
-
Re: Harmon Karden AVR 146 Won't stay powered
Ok, guys I took R_J's advice and checked voltage at each of the channels (white plugs with nothing connected). All are below 1 volt. Some were as low as .02 while others were at .07 and .08 and climbing until it shutdown. I thought about mucking with the bias, but thought I better wait until one of you experts provide some additional guidance.
Is it of any importance that the front panel is not displaying any information whatsoever OR is this normal assuming the unit is going into power fail? Also, looking at the schematic...Leave a comment:
-
Re: Harmon Karden AVR 146 Won't stay powered
Anyone? I was hoping to start troubleshooting this weekend.Leave a comment:
-
Harman Kardon AVR 146 Won't stay powered
I am a novice at this, but I am trying isolate a problem with my brother-in-law's Harmen Kardon AVR 146. I suspect a bad cap, but not sure where to start looking. I think it is going into Power Fail mode? I looked at the control boards I could visibly see and do not see anything standing out like a bulging cap or cracked solder connection.
I did do a full processor reboot and have all the speakers disconnected, but it still will not stay powered on, nor will the front screen show any signs of life.
The symptom:
With the system in standby mode, when... -
Re: New Members - please post your introductions here
New member and a novice at electronics, but I can work a voltmeter, repair car air-conditioners, rebuild engines, grew up with Unix and know firewalls. I am very diverse and love to learn, but be patient with me as I am an old dog learning new things. Looking forward to the forum.Leave a comment:
No activity results to display
Leave a comment: