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Author Topic: Crate MX 20 RC Won't Power On Fuses OK  (Read 1702 times)

gez239

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Crate MX 20 RC Won't Power On Fuses OK
« on: May 23, 2015, 04:01:56 AM »
hey guys I'm new to the forum and also new to opening amps but I got this little Crate with spring reverb I totally forgot about but want to see if I can get it back and running. I remember I used to use this amp for a short while (until it stopped working) in my car after my car radio got busted. I would have it plugged in with a ac to dc converter through the cigarette lighter and would just play music through that. it randomly stopped working and I put it away and forgot about it and I opened it up today and went and bought a new fuse for it but it still won't power on. I'm sure it had something to do with me running it through that cheap car converter. does anyone have any suggestions to what it may be? I appreciate any input.

Roly

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Re: Crate MX 20 RC Won't Power On Fuses OK
« Reply #1 on: May 23, 2015, 05:19:19 AM »
Hi gez239, welcome.


"Doc, I don't feel well - what could it be?"

Quote from: gez239
it randomly stopped working

For a start, give us more detail about how it failed, for example was it cutting on and off while you were using it, or did it sometimes fail to turn on when you flipped the switch?

Does the pilot light come on?

If so, have you tried it with an external speaker and/or headphones?

When it was "randomly" stopping was the pilot light staying on, or did it reflect it working or not?

Since it was your car sound system, did it take a tumble at some point?

Please post answers to the above questions.

Quote from: gez239
I'm sure it had something to do with me running it through that cheap car converter.

Maybe, maybe not.  Let's not jump the gun.  Here we work by first evaluating the symptoms, then making a possible diagnosis.  At this point it could be cancer, or it could be indigestion, or just about anything else in between.


{"randomly" suggests that it could be as simple as a dodgy connection, and is not consistent with damage due to running it from an inverter.}
If you say theory and practice don't agree you haven't applied enough theory.

J M Fahey

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Re: Crate MX 20 RC Won't Power On Fuses OK
« Reply #2 on: May 23, 2015, 06:03:57 AM »
Start by unplugging the amp, flipping the power switch ON, and measuring resistance vetween hot and neutral male power plug legs.
You are then measuring transformer primary resistance, which should be, say, from 5 to 20 ohms.
If you measure "open" then open the amp and remeasure straight at the transformer primary wires.
ALWAYS WITH AMP UNPLUGGED FROM MAINS POWER.

It *might*  be something as simple as a bad switch or fuse holder or mains cable.

Now if the power transformer is open ....  xP