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Author Topic: MP1 Tube board issues, like am radio  (Read 12873 times)

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monty

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MP1 Tube board issues, like am radio
« on: Time Format »

Hey everyone. I have jumped back into the ADA world this afternoon when the mailman delivered an MP1 to my doorstep  :banana-dance:

The seller had attempted to perform the mod4 but the tube modes sound bad. Like AM radio bad. It makes sound, seems like it might have less gain (hard to say since its been years since I've had an mp1), and the eq works fine. The Solid state mode sounds killer and the chorus works perfectly fine.

The work itself looks clean and fine. The only thing that stood out to me was that two of the ground wires from the tube board were soldered directly to the main board, which I haven't seen before. All the components look to be in the right spot and orientation but I haven't had a chance to verify the values according to the mod4 info. I will do that after work but in the meantime, any other ideas of what I can check?
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monty

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Re: MP1 Tube board issues, like am radio
« Reply #1 on: Time Format »

So I checked out the components and everything is correct  :???: The only thing missing/different are the cables F, J, N. Do both wires need to be connected to both boards for proper operation? I recall some of my old mp1s weren't all connected. With this one, two of the ground wires were soldered directly to the underside of the main board to one of the long traces.
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rnolan

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Re: MP1 Tube board issues, like am radio
« Reply #2 on: Time Format »

This is MJMP/Sparker territory, I'm sure they will help  :thumb-up:
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monty

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Re: MP1 Tube board issues, like am radio
« Reply #3 on: Time Format »

Long bump lol. Haven't had time to check things out again until now. Dug it back up and looking at it. Still scratching my head.
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MarshallJMP

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Re: MP1 Tube board issues, like am radio
« Reply #4 on: Time Format »

Seems you have an old B revision,can you make some pics of the inside?
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monty

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Re: MP1 Tube board issues, like am radio
« Reply #5 on: Time Format »

Yup can do. Anywhere in particular? I double checked the caps and resistors for the mod and everything reads correctly.
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monty

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Re: MP1 Tube board issues, like am radio
« Reply #6 on: Time Format »

Here are some photos:






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MarshallJMP

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Re: MP1 Tube board issues, like am radio
« Reply #7 on: Time Format »

On the 2nd pic i see that the shielded wire doesn't look to good.You see that the shield came out of the insulation,this wire carries the anode voltage which is 100V+,does it touch the resistors nearby.Check it and replace it if possible.
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monty

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Re: MP1 Tube board issues, like am radio
« Reply #8 on: Time Format »

The H wire? It's not touching anything but yeah needs to get cleaned up a bit. I soldered it back to the pin where it was. Still no difference though.
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RobbHell

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Re: MP1 Tube board issues, like am radio
« Reply #9 on: Time Format »

Monty check your Messages.
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monty

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Re: MP1 Tube board issues, like am radio
« Reply #10 on: Time Format »

Here's a video to show what it actually sounds like:
http://youtu.be/vs6r23pOi3E
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RobbHell

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Re: MP1 Tube board issues, like am radio
« Reply #11 on: Time Format »

Ok this the Second Error I found on the forum this week guys and a Big f*ck Up.

The Tube Conponet Layout PDF file has the PIN locations marked WRONG there Backwards. It Shows Pin 1 as Pin 9  No No No.
It shows the H Wire going to PIN 8,9. No wonder Monty is having a hard time.
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rnolan

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Re: MP1 Tube board issues, like am radio
« Reply #12 on: Time Format »

Hey Rob, thanks for the heads up, we will attempt to rectify but as it's a pdf of a scan I'm not sure how we'd fix it. Do you have a more accurate layout to post. Meanwhile we will add a Note: next to the link, alternately Dante my remove the pdf.

You say this is the second error ? I don't recall the first ? But let me know and I'll look into correcting it.

Again good pickup, but the words you use make it sounds like it's deliberate (a Big F#ck Up), bit harsh don't you think ? (I do)
Cheers R
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Dante

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Re: MP1 Tube board issues, like am radio
« Reply #13 on: Time Format »

Guys,

I do apologize for any incorrect schematics that are in place. I am not a technical guy, and have no idea what I'm looking at when I see a schematic, so forgive me.

That said, I can modify any images that need fixing, just clue me in and I'll take care of it. I have MAD photoshop skills. You want a picture of you and Lita Ford going to the prom? No problem!

Quote
a Big F#ck UP
: RobHell, thank you for pointing this out, but please be sure it was not intentional. Perhaps you have a flair for the dramatic, maybe less caffeine is in order, whatever. I just think Rnolan has a point here - that seems a bit harsh. Let's try to be nice to each other around here and help each other out - cool?

@Monty: If you're having trouble, can you reach out to MJMP for some advice?

RobbHell

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Re: MP1 Tube board issues, like am radio
« Reply #14 on: Time Format »

Yea I was on my third cup of Coffee lol. I know it's not intentional. Monty was asking some questions and I was wondering where he was coming from with his questions. I wasn't until I went through all the documents that I saw where the confusion was coming from.
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