RPA-1 Trigger Problem

[drfink]

I haven't needed to contact support in some time. I have an RSP-1 pre-amp and RPA-1 power amp, both purchased in late 2007, and both have been working fine for many years.



However, lately my RPA-1 has gradually developed a triggering problem, in which the amp flutters between ON and STANDBY states at random times. When the RPA-1 is working, there are no other issues, i.e. sound quality is fine with no hum or noise, and sound comes out of both speakers. At no time does the status LED go red -- it is always either blue or off.



Here's what I have done so far to debug this issue:



1. Opened both RSP-1 and RPA-1 units to blow them out with compressed air.



2. Checked all trigger switch options (ON, SIGNAL, TRIGGER) -- Result : The switch state makes no difference.



3. Disconnected RSP-1 trigger cable while RPA-1 trigger switch set to ON. Result : Negative, problem still remains.



4. Listened to RSP-1 preamp output through headphones while monitoring RPA-1 amp state. Result : RSP-1 output is steady while RPA-1 flutters between ON and STANDBY.



5. Disconnected speakers AT THE RPA-1, with trigger switch set to ON, to ensure no shorting problems external to the RPA-1. Result: Negative. Problem remains. I do notice in this configuration that the unit stays in the ON state longer upon initial startup (~ 45-60 seconds) before the fluttering problem develops, so this may point to a thermal issue.



I understand this unit is no longer under warranty, so I'm not expecting free service if I request an RA number. I'm just hoping someone may have seen this issue before, and have some other tests I can run, or perhaps know which component is at fault.



Thanks much!

[drfink]

NOTE: Applying 9V to the RSP trigger cable seems to result in a stable "ON" state for the RPA. Lonnie Vaughan suggested this could indicate that the RSP's trigger output is getting weak and might need to be serviced. However, this doesn't yet explain why setting the trigger mode switch on the RPA to "On" results in an unstable state, with "flickering".

[rdperry12]

I had this issue and had to replace the relay in both RPA1 that I have had. It is on a removable board right in the middle of the amp and is pretty easy to do if you can solder a little bit. I used Parts Express part # 075-128

[drfink]

Cool -- Thanks! We'll see if this jives with Lonnie's diagnosis, if/when I hear back from him.