Premier 18LS with no output from the Main outs

[chalfont]

Hi ,

Can anyone help with this issue.
Both EPL 1and 2 outs are fine.

Very grateful thanks for any help

[admin]

First, welcome to the forum. Great to have you with us.

Have you opened it up to see if there is any connections broken? Any sign of clear damage? How did this happen,... was it working before and just quit one day? Did it have any distortion before the main out stopped working?

BTW- I deleted the other double post of this so we can concentrate answers here.

[AnotherJohnson]

This is really really low hanging fruit ... but have you checked the mute button?

[chalfont]

Hi All,

Thank you for the welcome and your replies.
The serial number of the unit is 3401102

The unit belongs to a friend and it was working fine until about a week ago when he turned it on and there was no output at all.
I have taken the top off and no signs of any damage visible at all.
All the rear connectors are sound.
The Mute function works as do the level control cursors.

The signal on the EPL output look clean and fine checked with a scope.
I really need schematics to trace the output signal path.

Thanks again

[admin]

Unfortunately, I don't believe we have the 18's schematics in our database. If only the main output is not functioning, you can try to trace the leads on the circuit board. There are a fair number of components in the premier 18 so granted this may be a challenge.

[chalfont]

Are you able to help me with the whereabouts on the main pcb the output signals to the output relay from as there is no signal on the relay but the relay itself is functioning perfectly?

Thanks

[admin]

Wish I could help but I am not really familiar with the 18LS. If sending it in to CJ is not a viable option you could backtrack the signal path with the continuity setting on a multimeter. Not sure how "crowded" the board looks so this may be easier or harder depending on access to the circuit board. You may need access to the underside of the board as well.

The EPL outputs are basically designed for external processors. Can you control the volume on the EPL outputs? If so, it may be that the issue is somewhere between the volume control and the output connector. But this is kind of a stretch as again, not really familiar with the 18LS and don't have access to the schematics.

[roberto]

Hola and welcome,
The EPL 1 and 2 are passive, you might have a problem in the power supply. Do you have a tester?

[chalfont]

Yes, I certainly do. Are you able to point me in the direction of the components that I need to check?

Thanks again

[chalfont]

The problem does indeed lie with the power supply.
F2 on the PCB looked intact but when measured was blown.
I checked the AC voltages ou of the 2 red secondaries and the center-tapped blues.
I have 72 V out of the two red and 42 V out of the centre tapped blues.

The 5v and 18 v rails are fine but and on checking the current draw across F", measured 1.6A so could not understand why it blew.
However replacing it, it causes F1 on the rear to vaporize and the unit just dies.
Diodes D4 D5 D6 and D7 all measure fine.

Help please !

[chalfont]

I have found the problem : C20 has gone dead short

[AnotherJohnson]

Congratulations!

[chalfont]

My problem now is obtaining a replacement.

[AnotherJohnson]

[roberto]

Please excuse me for my poor follow through of your post. The Internet here in Costa Rica is not working right. It is so good that you found the bad capacitor. At the below address you can find good quality parts at a fair price:

https://www.parts-express.com/search?ke ... vance:desc

Good to know that you did find the problem...excellent job! Right at the power supply. The problem made sense that the circuit protection was not acting.

Again, good job!

[admin]

I second parts-express. Have bought from them many times they are very reliable and probably have the best selection of electronic components of any online store.

I've also had good experience with the solen brand caps. I just recently did a cap replacement for one of my speaker crossovers and used solen.

[chalfont]

Thank you all for your feedback and have taken a look at Parts Express.
The cap is a 0.5uf 100V Polyproplene +/-10% and they do not have this specific value.

Its either 0.47 or 1uf...?

[AnotherJohnson]

Either should be fine.

Try both and see what you think.

[admin]

If you are going with solen, you can order directly from their company. They are in Canada so shipping takes a little longer than parts-express but they will have a better selection of Solen caps.

[roberto]

0.47uF @ 100V or more will do.