Leak 2000

[112stereo]

Just purchased a couple of amps which are in a bad way. I mainly bought them for spares.
The Leak 2000 seemed OK after a through check I plugged it in and it worked.
The radio played but very quiet, so I tried an input in the aux socket and that was the same.
However, when I turned it off for a second I was blasted at full volume.
I left it for a while and checked all connections and tried it again and the same thing happened. I can only conclude the current limiter is coming on. Any ideas how I can proceed ?
All pots and switches seem OK and I am getting equal sound from both channels.

[Ted Kendall]

It doesn't sound like the protection circuit to me - I'd guess you are losing it somewhere in the preamplifier. These things have switched gain on the inputs, if memory serves, and you may have dirty switch problems or the like. It's best to put a signal in and trace it through the amplifier tp get a better idea of what's going on.

[vinrads]

Most likely to be dirty switches these are known for this , clean all the push button switches on the front and rear , in the past I had to resort to squirting some Brasso in the switch working it a few times then flushing it out with switch cleaner , Mick.

[audiomagpie]

Common fault with these, there's a simple protection circuit that grounds the audio input to the power amp at switch on/off for a couple of seconds. There's a 100uF cap (C27) that needs changing, it goes 'Leaky' I must have done 4 over the years...
Simple repair but you do have to disconnect the power amp board to upturn it to get at the track side. They do sound good when working well...

[112stereo]

Ok. Thanks guys I will look at these points tomorrow.

[audiomagpie]

It's the larger electrolytic in the photo here right against the chassis rail..

[112stereo]

Found it and it's done that job. Plenty of volume now but very distorted as though the speakers have collapsed! Will now work through the power stage , could still be a bad connection somewhere. Checked all switches and all ok I think someone has looked before as signs of switch cleaner on some. All inputs work and so does the radio on all wavelengths. Wish I had a scope still.
Still it will keep me quiet for a while, not in any hurry to get it fixed little and often is my motto.

[vinrads]

Nice one ,not had that before , Mick.

[112stereo]

Double checked the switch and can't fault them.
Other than the psu and the switches I can't find another common link between the channels when plugged into the main amp and pre-amp socket at the back which seems to override the front panel controls. The psu is supplying 29volts against the stated 32 volts but it's stable with sound on or off.
I could start changing caps, but would the same cap on both channels be faulty? I'll sleep on it and try again tomorrow.

[112stereo]

Just lifted c27 and again when I turned it off the sound blasted out just for a second, but it was clear, loud full of bass. Reconnected c27 and the sound although loud was very distorted and flat like a mobile phone, could there be another fault in this circuit ?

[112stereo]

Fixed.
Dry joint on the psu. Must have disturbed it when I took the board out to replace the cap.
Many thanks to all for their support.

[audiomagpie]

Just caught up with this post, glad you sorted it!