MF A100 fans problem - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 6th June 2011, 12:08 PM   #1
miligor is offline miligor  Serbia
diyAudio Member
 
Join Date: Nov 2004
Location: KI
Default MF A100 fans problem

Fans not working. After one hour amplifier is very hot, but fans still not started up... Is it problem with termo-switch or what?
  Reply With Quote
Old 6th June 2011, 12:37 PM   #2
jez is offline jez  United Kingdom
diyAudio Member
 
Join Date: Jan 2004
Location: n.e england
There is no thermal switch for the fans on an A100. They should be running all the time! If not then the most likely fault is dry soldered joints. The wires to the fans sometimes get broken when people open up the case also...
__________________
Repairs and mods to Real Hi-Fi, guitar amps and P.A. in North East England. http://www.arklesselectronics.com
  Reply With Quote
Old 6th June 2011, 12:46 PM   #3
effebi is offline effebi  Italy
diyAudio Member
 
effebi's Avatar
 
Join Date: Nov 2010
Location: Milan
Measure voltage at fan input.
If voltage present replace fan. If you can't find the original, get a good one, like PAPST (sold by major electronics distributors). Avoid cheap chinese computer fans.
effebi
  Reply With Quote
Old 6th June 2011, 01:02 PM   #4
jez is offline jez  United Kingdom
diyAudio Member
 
Join Date: Jan 2004
Location: n.e england
It's very unlikely that the fans are faulty. They are Papst.... They sometimes become noisy but I can't recall one stopping altogether other than from dry joints/faulty wiring or the other common one is that the aluminium ducts around them can easily become bent and foul the fan blades.
__________________
Repairs and mods to Real Hi-Fi, guitar amps and P.A. in North East England. http://www.arklesselectronics.com
  Reply With Quote
Old 6th June 2011, 06:40 PM   #5
miligor is offline miligor  Serbia
diyAudio Member
 
Join Date: Nov 2004
Location: KI
Yes, it is Papst TYP 971TR 12V 50/60Hz 68uF ??? What's this? One wire is cut off from pcb, and both of them are connected over one bipolar 20uF elko??? TYP971TR have 3 wires, brown, blue and yellow... What is this 3 wires?
  Reply With Quote
Old 8th June 2011, 09:23 AM   #6
miligor is offline miligor  Serbia
diyAudio Member
 
Join Date: Nov 2004
Location: KI
Something like this:
Attached Images
File Type: jpg A100 fans.jpg (82.6 KB, 135 views)
  Reply With Quote
Old 8th June 2011, 11:42 AM   #7
jez is offline jez  United Kingdom
diyAudio Member
 
Join Date: Jan 2004
Location: n.e england
It's certainly something like that yes. There may be a resistor (a Wirewound) in circuit also from memory but can't swear to it..... I have repaired loads of these (used to work for MF) but I don't have one here to check at the moment and the schematic does not show the wiring to the fans.
__________________
Repairs and mods to Real Hi-Fi, guitar amps and P.A. in North East England. http://www.arklesselectronics.com
  Reply With Quote
Old 29th August 2011, 08:45 AM   #8
miligor is offline miligor  Serbia
diyAudio Member
 
Join Date: Nov 2004
Location: KI
Fans are OK. One brown wire was de-soldered from pcb...
  Reply With Quote
Old 31st December 2011, 01:31 AM   #9
diyAudio Member
 
Join Date: May 2009
Following on from this issue, the (2) my fans in my A100 are noisy (especially when I switch off.
I havent confirmed the exact specification of mine but is there a direct replacement avaialble?
  Reply With Quote
Old 24th January 2012, 01:25 AM   #10
diyAudio Member
 
Join Date: May 2009
I've since confirmed mine are the same type - 2x PAPST TYP971TR 12V AC 50/60HZ 68microF.

I also checked with PAPST UK and they dont have a direct replacement

"........... was made obsolete many years ago. Looking at the specification of the fan unfortunately there isn’t anything we could offer as an alternative from our current range....... airflow of the fan was 6.8 litres/sec (24.5 m3/hr), was rated at 12 volts A.C. and had a maximum ambient temp of 70 degrees C."

Also the mounting bracket is 85mm (between centre of each mounting hole) and fan diameter is 60mm. It obviously need to be quiet as well.

If ayone has an idea where I can get replacement I'd be glad to hear from you
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Musical Fidelity A100 fans willholmania Solid State 3 18th March 2014 08:52 PM
Musical Fidelity A100 problem. willholmania Solid State 2 23rd July 2010 08:08 AM
Bridging MF A1 or A100? rmgvs Solid State 14 29th March 2009 08:56 PM
MF X A100-R anyone done mods ??? MadMutt Solid State 4 18th May 2008 11:00 AM
Anyone have a good, clear schematic of the MF A100? qboneus Solid State 20 8th March 2004 08:17 AM


New To Site? Need Help?

All times are GMT. The time now is 09:09 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2