ADC-420: Some stops are 'quiet'

[Guest]

My wife's family has owned an Allen ADC-420 since new in 1980. We are now the owners of it, 30 years later!</p>

A bunch of weeks ago the ability to adjust the expression pedal went out. Thanks to this forum I picked up a light bulb and got everything working again! Thanks for that!</p>

For 2 weeks everything has worked great. Now I have what I think is an unrelated problem but maybe not.</p>

Some stops, mostly the 8' and 16' stops do not play with any volume. Others work as they should. For the 8' and 16' stops, if you select them one at a time you can hear that each of the stops is actually producing sound, it is just very quiet (cup your ear and you hear it quiet). </p>

Any ideas?</p>

Any other questions?
</p>

[DellAnderson]

Re: ADC-420: Some stops are 'quiet'

[quote user="SE-Mark"]

Some stops, mostly the 8' and 16' stops do not play with any volume. Others work as they should. For the 8' and 16' stops, if you select them one at a time you can hear that each of the stops is actually producing sound, it is just very quiet (cup your ear and you hear it quiet). </p>

[/quote]</p>

Mark,</p>

I don't have the answer but as some know, I have the same problem (with some of the pedal 8 &amp; 16 stops). Can you be more specific about which stops exactly seem too soft? Mine turned out to be on a particular TG card that I was able to adjust upwards but only very slightly - it is still unsatisfactory to me but waiting definitive diagnosis and treatment (to include suggestions from board members here such as remove (and replace after cleaning contacts, each EPROM chip on the appropriate cage card(s)).
</p>

[Guest]

Re: ADC-420: Some stops are 'quiet'

Thanks for the start Dell.

Here is the stop list of affected stops from my wife...

Swell
Bourdon 16
Viola 8
Sp. Prin. 4
Kop. Flute 8
Tromp 8

Great
Prin 8
Kop Flute 4
Sup. Octave 2
Tromp 8

Pedal
Bourdon 16
Lieb. Gedekt 16
Octave 8
Tromp 8

I also got the date that they received the organ wrong... should have been 1991, not 1980. Oops. Only 20 years old.

[MarkS]

Re: ADC-420: Some stops are 'quiet'



This is a two channel organ of about fourteen stops. One of the two channels is weak. </p>

Swap the input cables to the amplifier/amplifiers. If the voices you listed (really just seven stops) are now strong and the others are weak, then the problem is in the amplification or speakers. Otherwise it is likely a dirty potentiometer on that channel of the tone generation board. </p>