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Post subject: Roc Pro 1000 - No Sound, No LED's, but do get sound from S/R
Posted: Fri Jul 05, 2013 6:48 pm
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I have a Roc Pro 1000 that doesn't output any sound from the inputs, doesn't light the front LED's, the Reverb Tank makes no jangling when smacked but I do get sound on the Send and Return. I've replaced all the OP AMP's, Thermistor (was burnt off the board), the HV Diodes, the J111 FET's, the LM4040D and a couple of ugly looking caps. Reading correct voltage on all OP Amps accept the ones before the preamp stage.

Lost at this point. Could it be the J113's or MC1436 or perhaps a couple of zeners? I put a 1KHz sine through it and my scope sees it up until the first OP AMP so I replaced it again and still no luck.

All help is greatly appreciated.

Thanks,

PD


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Post subject: Re: Roc Pro 1000 - No Sound, No LED's, but do get sound from
Posted: Sat Jul 06, 2013 12:47 am
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DX7Man wrote ; " I put a 1KHz sine through it and my scope sees it up until the first OP AMP so I replaced it again and still no luck. "
____________


The first OP amp I see is just after the input jacks ; U1a That's the one ? Voltage are good at this OP amp ?

You write you have sound at sound return jacks wich one ? Both ?
Send is a Preamp output
Return is "Power" Amp Input

If you got your 1 khz signal at Send, OP Amp U1a must be ok.


Link for schematic ; That is the one you use ?

http://support.fender.com/schematics/gu ... ematic.pdf


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Post subject: Re: Roc Pro 1000 - No Sound, No LED's, but do get sound from
Posted: Sat Jul 06, 2013 9:08 am
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Yep, that's the schem I'm using and it is U1A I'm referring to; but I'm only getting 12v volts off pins 4(-) and 8(+) and to correct myself; it's the return I get output through the amp on, sorry bout that.


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Post subject: Re: Roc Pro 1000 - No Sound, No LED's, but do get sound from
Posted: Sat Jul 06, 2013 1:40 pm
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Sounds like you have a power supply issue, particularly the +/- 16 volt supply.

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Post subject: Re: Roc Pro 1000 - No Sound, No LED's, but do get sound from
Posted: Sat Jul 06, 2013 3:11 pm
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I checked the transformer and it was fine; the other OP AMP's after the pre-amp read the correct voltage. Could it still be the xformer you think?

Thanks,

PD


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Post subject: Re: Roc Pro 1000 - No Sound, No LED's, but do get sound from
Posted: Sat Jul 06, 2013 8:54 pm
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DX7Man wrote:
I checked the transformer and it was fine; the other OP AMP's after the pre-amp read the correct voltage. Could it still be the xformer you think?

Thanks,

PD


Suggest you reread shimmilou's post. He didn't say to check the transformer. He said to check the +/- 16 volt power supply. There's more to the power supply than the transformer.

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Post subject: Re: Roc Pro 1000 - No Sound, No LED's, but do get sound from
Posted: Sun Jul 07, 2013 5:36 am
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bluesky636 wrote:
DX7Man wrote:
I checked the transformer and it was fine; the other OP AMP's after the pre-amp read the correct voltage. Could it still be the xformer you think?

Thanks,

PD


Suggest you reread shimmilou's post. He didn't say to check the transformer. He said to check the +/- 16 volt power supply. There's more to the power supply than the transformer.


+1

DX7Man , be careful , you want to fix your amp and that's great but your lack of experience and knowledge could be costly . Read carefully everything on this forum .


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Post subject: Re: Roc Pro 1000 - No Sound, No LED's, but do get sound from
Posted: Sun Jul 07, 2013 7:44 am
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With respect, I actually have a great deal of experience, unfortunately I had an Ischemic stroke recently and still healing. It caused some memory issues that are slowly returning and thus casts the appearance of ignorance. It's been frustrating for me to say the least; to be challenged with things I once could do in my sleep. Have patience with me if you will please, my apologies.

Thanks,

PD


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Post subject: Re: Roc Pro 1000 - No Sound, No LED's, but do get sound from
Posted: Sun Jul 07, 2013 8:39 am
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DX7Mann,
I did not mean to insult or be unpleasant talking about your apparent lack of experience but I do not know you I can only rely on me what I read.

And besides, my mother tongue is French Canadian, not American or English language.

By the way , as American did you prefer I said you speak American or you speak English ?


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Post subject: Re: Roc Pro 1000 - No Sound, No LED's, but do get sound from
Posted: Sun Jul 07, 2013 10:23 am
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American would actually be the accurate denotation; we yanks don't speak true English (even though most think we do), lol. I understand entirely how text and messages don't properly convey tone and all that. I'm not offended, I'm too old and been through way to much for that; I simply wanted to point out the issues I've been having and convey that it makes me look like a buffoon and how frustrating it is personally (my fault is pride and I've always been "the go to guy"). I did not intend to cast any negativity towards you or come across as taking a shot at you; it was not my intention at all and sorry if it came across that way.

Thank you for your understanding and humble disposition; rare qualities in this day and age.

Thanks,

PD


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Post subject: Re: Roc Pro 1000 - No Sound, No LED's, but do get sound from
Posted: Sun Jul 07, 2013 11:16 am
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+1


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Post subject: Re: Roc Pro 1000 - No Sound, No LED's, but do get sound from
Posted: Sun Jul 07, 2013 11:20 am
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I'm thinking the issue perhaps has something to do with the zeners or cap leading up to U1 or U2. The LED's not lighting up makes me think that there's an under volt issue or broken trace. This started with someone connecting an overdrive pedal to it and there's no limiting circuit (that I can see) on the input. Perhaps this damaged the tant cap, zeners or both...

Thoughts?

Thanks,

PD


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Post subject: Re: Roc Pro 1000 - No Sound, No LED's, but do get sound from
Posted: Sun Jul 07, 2013 11:21 am
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stratele52 wrote:
+1


+2

No harm, no foul.

Happy to have you aboard, sir.

Arjay

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Post subject: Re: Roc Pro 1000 - No Sound, No LED's, but do get sound from
Posted: Sun Jul 07, 2013 11:25 am
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Okay, I'm going to get teary eyed now with you guys. I believe that I have indeed landed in a forum of good hearted, respectful individuals.

Thank you,

PD


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Post subject: Re: Roc Pro 1000 - No Sound, No LED's, but do get sound from
Posted: Sun Jul 07, 2013 11:50 am
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DX7Man wrote:
I'm thinking the issue perhaps has something to do with the zeners or cap leading up to U1 or U2. The LED's not lighting up makes me think that there's an under volt issue or broken trace. This started with someone connecting an overdrive pedal to it and there's no limiting circuit (that I can see) on the input. Perhaps this damaged the tant cap, zeners or both...

Thoughts?

Thanks,

PD


I really think you need to check the +/- 16 volt supply as already suggested if you are only seeing 12 volts on the ICs. I've never heard of an OD pedal damaging the front end of an amp before.

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