Seeburg AY160 selection problem

Help
Have a problem with the AY160 I'm restoring, I'm trying a new pulse
amp (when I say new I of course mean another second hand one) and this
is better than the old as it seems to sometimes select a record, about
1 in 15.
Am I correct in assuming that this wouldn't be the tube on the pulse
amp as I have changed the cap in the pulse amp, the tube glows fine
and as I mention, it does sometimes select.
I have not yet changed the caps in the Tormat unit, would this
possibly cause an intermittent selection problem? The troubleshooting
guide has all but led me to a faulty pulse amp (unlikely with 2) or a
duff 12ax2 tube (I think that's what it is)
Any ideas anyone
Cheers
shaun

My experience has been that you need to do more to repair a pulse amplifier
than simply replacing the coupling capacitor. There are about eight resistors
inside the pulse amp that suffer ill effects (significant shifts in value)
from all the heat trapped inside the pulse amp. A full rebuild of the pulse
amp should involve replacing all the resistors in addition to the coupling
capacitor.

The selection receiver chassis also suffers similar problems. The 470K and
56K resistors connected to the pulse amp socket tend to get roasted and drift
significantly in value. There is a 2.2M resistor connected to the 6X4 (?)
tube socket, and a 36 ohm resistor inline with the readout circuit that are
also prone to problems.

Replace all the caps in the selection receiver and test all the resistors for
proper value. Once you've done this the system is remarkably stable.

Remember that selection problems can also be due to issues with the write-in
circuitry inside the selection receiver and credit unit. A dirty write-in
contact on the credit unit can contribute to erratic selection operation.

A dirty read-out detent switch on the carriage can also contribute to erratic
selection operation.

Your best bet is to use the flashlight battery trick outlined in the manual to
try to isolate the issue to a specific area - write-in, read-out, or sense.
Or just cut your losses and fully rebuild the pulse amp and receiver.

Joseph "Tony" Dziedzic

In article ,
(Shaun) wrote:
Help
Have a problem with the AY160 I'm restoring, I'm trying a new pulse
amp (when I say new I of course mean another second hand one) and this
is better than the old as it seems to sometimes select a record, about
1 in 15.
Am I correct in assuming that this wouldn't be the tube on the pulse
amp as I have changed the cap in the pulse amp, the tube glows fine
and as I mention, it does sometimes select.
I have not yet changed the caps in the Tormat unit, would this
possibly cause an intermittent selection problem? The troubleshooting
guide has all but led me to a faulty pulse amp (unlikely with 2) or a
duff 12ax2 tube (I think that's what it is)
Any ideas anyone
Cheers
shaun

Hi
I thought as much, I will recap and check both areas, it would appear
its a pulse amp problem when going through the problem guide. Actually
when its first turned on it usually selectes about twice no problems
then fails (as if its caused by heat) which would lead to a cap
failing or a resisior heating up and going out of tolerance.
Cheers
Shaun

(Joseph A. "Tony" Dziedzic) wrote in message news:Xzs1c.111163$4o.128937@attbi_s52...
My experience has been that you need to do more to repair a pulse amplifier
than simply replacing the coupling capacitor. There are about eight resistors
inside the pulse amp that suffer ill effects (significant shifts in value)
from all the heat trapped inside the pulse amp. A full rebuild of the pulse
amp should involve replacing all the resistors in addition to the coupling
capacitor.

The selection receiver chassis also suffers similar problems. The 470K and
56K resistors connected to the pulse amp socket tend to get roasted and drift
significantly in value. There is a 2.2M resistor connected to the 6X4 (?)
tube socket, and a 36 ohm resistor inline with the readout circuit that are
also prone to problems.

Replace all the caps in the selection receiver and test all the resistors for
proper value. Once you've done this the system is remarkably stable.

Remember that selection problems can also be due to issues with the write-in
circuitry inside the selection receiver and credit unit. A dirty write-in
contact on the credit unit can contribute to erratic selection operation.

A dirty read-out detent switch on the carriage can also contribute to erratic
selection operation.

Your best bet is to use the flashlight battery trick outlined in the manual to
try to isolate the issue to a specific area - write-in, read-out, or sense.
Or just cut your losses and fully rebuild the pulse amp and receiver.

Joseph "Tony" Dziedzic

In article ,
(Shaun) wrote:
Help
Have a problem with the AY160 I'm restoring, I'm trying a new pulse
amp (when I say new I of course mean another second hand one) and this
is better than the old as it seems to sometimes select a record, about
1 in 15.
Am I correct in assuming that this wouldn't be the tube on the pulse
amp as I have changed the cap in the pulse amp, the tube glows fine
and as I mention, it does sometimes select.
I have not yet changed the caps in the Tormat unit, would this
possibly cause an intermittent selection problem? The troubleshooting
guide has all but led me to a faulty pulse amp (unlikely with 2) or a
duff 12ax2 tube (I think that's what it is)
Any ideas anyone
Cheers
shaun