Help with pipe organ multiplex transmission system - UK Vintage Radio Repair and Restoration Discussion Forum

petertheorgan · 23rd Jan 2018, 12:17 am

I never cease to be amazed at the fount of knowledge that appears on this forum so I am wondering if there is anybody who can give me some guidence or point me in the correct direction,
In one of my other lives , I help out the local pipe organ builder and one of the instruments that we tune has a 30 year old multiplex transmission system and half of the system has died .
The firm that constructed the system is no longer in business and it would be a shame to have to charge the church a five figure sum to replace the system in its entirety.
Any help would be very much appreciated
please feel free to PM me
Thanks in anticipation
Peter.

Ps - Moderators, please feel free to move , re title , or delete if you feel that is appropriate

Radio Wrangler · 23rd Jan 2018, 7:37 am

30 years back, it could be done with standard logic ICs, or with a pair of microprocessors doing some of the work.

I'm assuming you've already exercised all connectors and IC sockets?

Some CMOS parts are showing horrible failure rates due to corrosion from moisture ingress and leaching phosphorus from the glass overcoat on the silicon.

As half the system is working, which half will give some clues to where there is most probably a single failed device.

The first step is either to find circuit diagrams, or to trace it all out. A lot of work, but you can then advertise your capabilities

there will be more of those systems out there...

For continued reliability, do you do a pre-emptive strike and stuff all new logic parts on the board? or replace all of the type which died? or just the one dead one?

Without any more info to go on, that's about all I can theorise.

David

Jonster · 23rd Jan 2018, 10:13 am

I'd start by making sure the power supplies are spot on with no ripple and reaching their intended destinations without voltage drop caused by oxidised connectors etc.

cmjones01 · 23rd Jan 2018, 10:44 am

Sounds intriguing. Can you post any pictures of what the electronics looks like, so we can get an idea of how it's made and what the likely failure modes might be?

Chris

dazzlevision · 23rd Jan 2018, 3:03 pm

Hello Peter,

I have sent you a PM, as I have a friend who works regularly with church/public hall organs and has repaired TDM systems used in such installations. He may well be able to assist you.

Regards,

Dazzle vision

23rd Jan 2018, 12:17 am	#1
petertheorgan Hexode Join Date: Dec 2006 Location: Bromley, Kent, UK. Posts: 332	Help with pipe organ multiplex transmission system I never cease to be amazed at the fount of knowledge that appears on this forum so I am wondering if there is anybody who can give me some guidence or point me in the correct direction, In one of my other lives , I help out the local pipe organ builder and one of the instruments that we tune has a 30 year old multiplex transmission system and half of the system has died . The firm that constructed the system is no longer in business and it would be a shame to have to charge the church a five figure sum to replace the system in its entirety. Any help would be very much appreciated please feel free to PM me Thanks in anticipation Peter. Ps - Moderators, please feel free to move , re title , or delete if you feel that is appropriate

23rd Jan 2018, 7:37 am	#2
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,869	Re: help with pipe organ multiplex transmission system 30 years back, it could be done with standard logic ICs, or with a pair of microprocessors doing some of the work. I'm assuming you've already exercised all connectors and IC sockets? Some CMOS parts are showing horrible failure rates due to corrosion from moisture ingress and leaching phosphorus from the glass overcoat on the silicon. As half the system is working, which half will give some clues to where there is most probably a single failed device. The first step is either to find circuit diagrams, or to trace it all out. A lot of work, but you can then advertise your capabilities there will be more of those systems out there... For continued reliability, do you do a pre-emptive strike and stuff all new logic parts on the board? or replace all of the type which died? or just the one dead one? Without any more info to go on, that's about all I can theorise. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

23rd Jan 2018, 10:13 am	#3
Jonster Heptode Join Date: Apr 2008 Location: Eastbourne, East Sussex, UK. Posts: 671	Re: help with pipe organ multiplex transmission system I'd start by making sure the power supplies are spot on with no ripple and reaching their intended destinations without voltage drop caused by oxidised connectors etc.

23rd Jan 2018, 10:44 am	#4
cmjones01 Nonode Join Date: Oct 2008 Location: Warsaw, Poland and Cambridge, UK Posts: 2,677	Re: Help with pipe organ multiplex transmission system Sounds intriguing. Can you post any pictures of what the electronics looks like, so we can get an idea of how it's made and what the likely failure modes might be? Chris __________________ What's going on in the workshop? http://martin-jones.com/

23rd Jan 2018, 3:03 pm	#5
dazzlevision Dekatron Join Date: Sep 2003 Location: Near Swindon, North Wiltshire, UK. Posts: 3,611	Re: Help with pipe organ multiplex transmission system Hello Peter, I have sent you a PM, as I have a friend who works regularly with church/public hall organs and has repaired TDM systems used in such installations. He may well be able to assist you. Regards, Dazzle vision