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Author Topic: Fender Pro 185 2x12 - New Problem Child  (Read 1116 times)

MurphyPeoples

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Fender Pro 185 2x12 - New Problem Child
« on: July 01, 2017, 03:35:22 PM »
Hello! I'm onto my second project now that it's summer and it's way too hot to spend much time outside in the afternoons.

My Fender Pro 185 is a real head scratcher. I plug in to the amp and get sound. I'd say it's like the volume is set to "3". But the volume control does NOTHING. 0 to 10 - Nothing. Always at "3".

I'm pulling the board this afternoon. I've already checked put speakers and they are in fine shape and both receive and push sound.

Any insights would be appreciated. I'm thinking about changing out the volume control straight away, but will wait to here from you guru's on here.
Thanks !
Murphy

Enzo

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Re: Fender Pro 185 2x12 - New Problem Child
« Reply #1 on: July 01, 2017, 03:51:25 PM »
Pull the board?  I'd start by finding the problem first.

You suspect the control?  OK, but don't just replace it in hopes it is the thing, get out your ohm meter and see if the pot is open end to end and if the wiper to either end varies the resistance in a reasonable way.

MurphyPeoples

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Re: Fender Pro 185 2x12 - New Problem Child
« Reply #2 on: July 01, 2017, 05:24:04 PM »
Well, I put the whole amp on the bench, and sprayed down all the pots with D5. And Miracle of Miracle's - everything is great. Damn this thing is LOUD. (Thanks Enzo!)

I noticed that two of the input jacks were "Super Glued" together. Wiggled them a bit, and they came apart in my hand. LOL.

Thankfully the board looks hack free to me. More educated eyes might see something I don't though.  ;)

So I'm pulling the board anyhow to replace those. I'm posting a couple of photo's of "warm" spots on the board. I took pics of both sides.

It looks like the heat is from CR45, CR54, CR55. Just wondering if this is common enough to leave alone?

Thanks again!
Murphy
« Last Edit: July 01, 2017, 05:25:12 PM by MurphyPeoples »

Enzo

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Re: Fender Pro 185 2x12 - New Problem Child
« Reply #3 on: July 01, 2017, 08:23:05 PM »
zener dropping resistors?  The zeners get hot as do the resistors.

MurphyPeoples

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Re: Fender Pro 185 2x12 - New Problem Child
« Reply #4 on: July 03, 2017, 04:54:05 PM »
I believe it's a testament to how good Fender built these things 30 years ago. I reflowed the solder on the Capacitors, Cleaned out all the Pots, Replaced broken and cracked input jacks.
I fired her up, and WOW. Beautiful sound. Great Reverb! Just excellent overall.

I did learn one lesson though... this tear down I simply cut the reverb coax cables to get them out of the way. WRONG! .
It took me a good while to solder all the lines properly together and heat shrink them well. Sheesh. Lesson Learned.  ::)

J M Fahey

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Re: Fender Pro 185 2x12 - New Problem Child
« Reply #5 on: July 06, 2017, 07:36:15 AM »
And you forgot to add: LOUD!!!!!   :dbtu:

 

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