Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 125
Default AVR-1905 Denon receiver amp fooled me

Symptom: does not switch on. Will switch on unpredictably once every
50 tries. Digital 5volts is always available. Clock oscillator can be
observed at the syscons pins only if other vertical boards are plugged
in. Grounds for digital and analogue seem to be floating. Display may
either be blank or have some leds glowing.
The first time i powered up it worked. I gave an estimate. Now i'm
fooled. Ever since then it switched on just once. Help. What role does
the 6ch input board play in the syscons clock oscillator (a 12 Mhz 3
legged ceramic resonnator).
Jango

  #2   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 3,833
Default AVR-1905 Denon receiver amp fooled me

Ouch. I'm glad I'm not working on that one.

I'm going to make a really stupid suggestion. It sounds like a bad solder
joint. Somewhere.

Have you called Denon? It's possible this is a known problem.


  #3   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 125
Default AVR-1905 Denon receiver amp fooled me

I'm going to make a really stupid suggestion. It sounds like a bad solder
joint. Somewhere.


Hey William, thanks a ton, you were right. I found a print cut leading
to pin 40 (RESET) of the syscon. Damn break was under the ic. Your
"stupid" suggestion kept ringing in my head and it was'nt until i got
the entire mainboard with all the vertical boards plugged in (ground
wires soldered from all boards too), off the chassis that i found it.
I would have ordered a syscon, replaced it to no avail, next i'd have
suspected the VFL drive ic, replaced that too........
Looking back heres a clue that might have given me hope that the
syscon was'nt bust, Clock oscillator would be visible only when i'd
drain Vcc off the ic (set powered down) and repowered the unit. This
should have led me to suspect improper reset. I couldnt access reset
pin of the ic as the smd was under the pcb. I did solder a wire to the
reset transistor's collector to monitor it and found a clean reset.
Thanks again mate,
You have a good day
Jango.

Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Need help with Denon AV receiver Ken123 Electronics Repair 3 July 3rd 07 02:55 PM
3801 denon receiver [email protected] Electronics Repair 22 January 15th 07 12:24 PM
Denon CD Player/Receiver UD-M5 ibbotsnm Electronics Repair 3 June 11th 05 02:50 AM
Receiver: Denon AVR-3801 HiFi Electronics Repair 0 January 15th 05 12:09 AM
Help with Denon Receiver ES Electronics Repair 1 May 14th 04 12:54 AM


All times are GMT +1. The time now is 02:44 PM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"