How to open a Crate BX100 combo?

[Albert Kreuzer]

Hi all,

got a Crate BX100 bass combo with an intermittent fault from a friend. And now I can't open this %$§" thing to repair it.
Removed the four top screws, removed the two side screws, removed the corner screws - is there any trick to get the chassis out or should I just use brute force?
Any help appreciated, thanks in advance!

Albert

www.albertkreuzer.com

[Enzo]

It should fall loose. Is it perhaps just stuck to the roof? SLip a screwdriver between chassis and cab and see if it pops free. SOmetimes the grille wedges the front of the chassis. Try removing the grille and see if that helps. I forget the speaker wires on that one, so don't yank and rip them out.

[Albert Kreuzer]

Thanks Enzo,

it was the grille. I managed to push it out from behind, then the chassis came loose. Yes, I noticed the speaker wires, that was the next pain
I had to take the speaker out to disconnect the wires (what were they thinking?). First thing I did was to install a speaker jack.

The amp seems to work fine. I let it heat up under a felt cloth with a dummy load for an hour and poked around with a chopstick - everything ok, no intermittant

Well, I'm going to clean the FX loop jacks anyway, they look a bit oxygenized...
Any other known problems / where to look while I'm inside?

Thx again
Albert
www.albertkreuzer.com

[Enzo]

Without looking up that specific one, Crates with such problems are usually loop jacks needing contact burnishment, jacks needing resolder, large cement power resistors broken free of their solder. And of course check for cracked pots along the panel and their solder.

Speaker wires soldered to the board? usually they are push-on connectors. Extract the board part way and disconnect them. Might help to turn the amp on its side. If they are soldered, then forget that.

[Albert Kreuzer]

Hi Enzo,

the usual suspects with PCB construction

Cleaned the FX jacks, resoldered all the jacks, pots and cement resistors. Seems to work now (but that's what it seemed before...)

The speaker wires were too short to get the chassis out of the cabinet, so I had to go for the speaker first. Black one on a push-on, red one on a multi-pin connector, won't go through the hole in the chassis.
Now it's got a proper speaker jack and plug.

The grille was so tight I had to use a (big!) hammer and a piece of wood to get it back in. Do they shrink the cabinets after assembly?

Thanks fo your help.
Cheers,
Albert
www.albertkreuzer.com

[Enzo]

They don't, but wood shrinks and swells.

One thing I always do when I have these amps out. I MEASURE the resistance of the cutout contacts on the jacks. It should be under half an ohm - it ought to look like your probes are touching each other. If it measures like 2 ohms, it will work just fine, but that resistance tells you the contacts are not clean, and some other time they might not work - an intermittent problem. SO burnish the contacts of they show any resistance. If teh footswitch jacks get resistive, you can have unwanted self-channel changes and stuff.

I use a GC9337 - it is narrow enough to fit in the slots on a Cliff type jack. They sell something similar at MCM MCM Part #: 22-1235
www.mcminone.com

[jdelgado]

Help, please Crate BX100 distorting

Have just "rescued" my BX100 and found it distorts. It sounded like a blown cone, but I opened it up & checked (thanks, Enzo!). I checked the speaker w/another amp & it's OK.
Speaker "pops" quite a bit when powering down amp (like the pop when u power up a PA in the wrong order). Checked sound w/headphones & distortion is evident. Checked multipin red connector, it was loose. tightened it, but same results
Can anyone help me troubleshoot/fix this?