[Top] [All Lists]

Re: [Amps] Titan 425 power transformer question

Subject: Re: [Amps] Titan 425 power transformer question
Date: Mon, 6 Jun 2011 15:32:26 EDT
List-post: <">>
Hi Pete, I suggest you do more testing before writing off the  transformer. 
One failure scenario that would cause the described problem is a  surge 
limiting circuit that is not shorting out the limiting resistor in the  primary 
If you measure the 240/120vac line voltage right at the plate transformer  
primary, it should be quite steady during turn on.
If that checks ok, you can carefully do the same test on the transformer  
secondary. It should also be quite steady at turn on.
Happy hunting!
Gerald K5GW
In a message dated 6/6/2011 2:07:13 P.M. Central Daylight Time, writes:

A bug deposited a big glop of mud (+ larvae)  into the gap between one
of the PS caps of my Titan and also glued the top  of the cap to the side
of the power supply metal cover. The cover and the  rest of the case was
very well grounded and the PS fuses never blew, the  amp just stopped
working. I have no idea how long a mud/dirt short was in  place, but the
larvae obviously didn't make it out alive.
The cap  in question tested obviously bad and I made an exact
replacement. All eight  caps now behave the same now, except the voltage
across each varies by  1-5%.
I spent a few days reforming the caps while fretting that  the
transformer/rectifier by itself is only putting out about 1300 volts  in
the "high" setting.
With the caps in place there is only 1650  volts present (i.e. about
550 volts short of spec). If a 14 watt signal is  put into the amp
briefly the plate voltage dives to about 1kv and comes  back to 1650 over
the course of 3-4 seconds. All of the rectifiers are open  one way and
dropping 1/2 volt the other way (with a meter having a diode  test 
Am I correct to think the transformer is  toast?

Pete  AD4L
Amps mailing  list

Amps mailing list

<Prev in Thread] Current Thread [Next in Thread>