Repairing Warwick Streamer original preamp - now with pics

[dyerseve]

So I have a beautiful Warwick Streamer Stage 1 which I love dearly. Unfortnately the pre amp developed a crackling noise so i removed it to see if I could find the source of the noise. Unfortunately it one of those pre's that comes in a little black box that is then sealed with some kind of white silicon. Anyway, by the time I had managed to remove it from the case a couple of the wires had come loose and now I am left wondering if it was a loose wire or a fault with the pre itself. The pre is all suface mount components except a diode, a electrolytic cap and a variable pot (for setting the mid freq i believe). I am thinking of swapping the cap and pot out as they really the only components I can see developing a fault.
Does anyone have any experience with these pre's or know anyone I can send it off to to have a look and repair it properly for me. I am a reasonably proficient with a soldering iron but I would really like to get this 100% and looking original ie set back in the case and sealed in with the silicon or whatever it was.

It looks a lot like the one in the photo below except it has the trim pot for the mid:
[url="https://postimages.org/"][/url]

Here is a couple of pics of the actual PCB in question - can anyone here help to get it fixed/checked over please:

[url="https://postimg.org/image/32ysyewszv/"][/url]

[url="https://postimages.org/"][/url]

Edited November 9, 2017 by dyerseve

[dmccombe7]

My pre-amp from my 89 Thumb bass faile and i was unable to get the direct EMG replacement from Warwick as no longer manufatcured.
They supplied the MEC equivelant.
It was fitted by McIntyre Guitars in Edinburgh.

I had the same fault as you have described along with a popping type noise on occasions.
I checked all the usual things like cleaning the pots and checking the jack socket connection with a jack inserted.
I know how to solder and how to check soldering and it was def a problem with the pre-amp.

The crackling could have been down to a poor connection or maybe just the pots needing cleaned.

If i remember right the Warwick website or even try the Warwick forum for a schematic for yours.
I managed to get one for my Thumb quite easily.
That should tell you where the wires should be attached.

Dave

[dmccombe7]

Not sure if this is your model but i found it from doing a google search. Hope this helps.
Dave

[freddy4940]

You can find exactly which part you need here:

https://shop.warwick.de/en/Parts+for+Instruments/Parts+for+Basses/Electronics

You can probably find the exact part you need by finding your model on the Warwick website.

[dyerseve]

thanks guys, not exactly what I was after. I am not willing to pay £300 for something that I know for a fact costs about £5.00 to build. I already know the wiring of the pre out pins to the pots in the wiring loom, it's the actual schematic of the PCB that I need so I can see the values and hopefully the part numbers of the components I want to replace.

[dmccombe7]

I've never seen what's inside the encapsulated PCB so can't help with that.
You could try searching for a schematic of the newer MEC equivelant as it will probably be pretty similar. Its not encapsulated and all components are clearly visible on the board.
The Thumb bass has different pot set up so not sure if a pic of my Thumb bass circuit board would be any help. That's assuming you can see it when the rear cover plate is removed. I don't fancy removing the board to take a pic.

Dave

[machinehead]

I had the same problem recently with my Streamer LX. I managed to download a pdf schematic drawing for the system but not for the PCB.

If it's any help I can take a pic of my PCB in the hope that your encapsulated one is the same. Let me know if you want a pic and diagram.

Frank.

[dyerseve]

thanks guys, I have now added photos of the PCB in my original post so hopefully here can point me in the direction of some electornics wiz who can help fix it.

[Grangur]

What was crackling in the circuit when it was in the bass?

Did the crackles happen when you adjust a pot? or when you move when playing the bass? or when you touch a pickup?
Or did it happen when it's laying on it's back on the floor and you pick a string?

I ask this, because it's far more likely that the problem is a pot, or a poor wiring connection than a faulty pre-amp. Physical problems are much more probable than an electrical problem.

I too have a Streamer Stage 1. If you're stuck, send your complete Pre-amp assembly to me and I'll take a look.

EDIT:
Yes, it's very probable the problem is the wires that have come loose.

Offer still stands - post it to me and I'll re-connect it and check it out in my streamer and check out any pots as needed as I can swap out bits with mine to find out exactly where any problem lies. I can do it over the weekend and back to you early next week, as long as we don't need new parts.

Edited November 9, 2017 by Grangur

[roman_sub]

John East really knows his stuff, but unsure if he'd take on repair of a Warwick preamp! I normally deal with Guitar Aid in London - maybe they could look at it, if you post it? If you do go down such a route, maybe send them the whole harness (pots etc) so they wire it up and save you some time in process.

TBH I never thought Warwick electronics were that good, so consider direct replacement for East / Aguilar / Bartolini etc etc... may be quicker and simpler.

[machinehead]

[quote name='Grangur' timestamp='1510235744' post='3404879']
What was crackling in the circuit when it was in the bass?

Did the crackles happen when you adjust a pot? or when you move when playing the bass? or when you touch a pickup?
Or did it happen when it's laying on it's back on the floor and you pick a string?

I ask this, because it's far more likely that the problem is a pot, or a poor wiring connection than a faulty pre-amp. Physical problems are much more probable than an electrical problem.

I too have a Streamer Stage 1. If you're stuck, send your complete Pre-amp assembly to me and I'll take a look.

EDIT:
Yes, it's very probable the problem is the wires that have come loose.

Offer still stands - post it to me and I'll re-connect it and check it out in my streamer and check out any pots as needed as I can swap out bits with mine to find out exactly where any problem lies. I can do it over the weekend and back to you early next week, as long as we don't need new parts.
[/quote]

That's a very generous offer indeed. The spirit of basschat is alive and well.

Frank. (And I tend to agree with Grangur's initial thoughts on how best to tackle this problem.)

[dyerseve]

[quote name='Grangur' timestamp='1510235744' post='3404879']
What was crackling in the circuit when it was in the bass?

Did the crackles happen when you adjust a pot? or when you move when playing the bass? or when you touch a pickup?
Or did it happen when it's laying on it's back on the floor and you pick a string?

I ask this, because it's far more likely that the problem is a pot, or a poor wiring connection than a faulty pre-amp. Physical problems are much more probable than an electrical problem.

I too have a Streamer Stage 1. If you're stuck, send your complete Pre-amp assembly to me and I'll take a look.

EDIT:
Yes, it's very probable the problem is the wires that have come loose.

Offer still stands - post it to me and I'll re-connect it and check it out in my streamer and check out any pots as needed as I can swap out bits with mine to find out exactly where any problem lies. I can do it over the weekend and back to you early next week, as long as we don't need new parts.
[/quote]

Hey Richard thanks very much for your very kind offer. I will have another crack at it over the next few days just to make sure it wasn't a loose wire.
Just to clarify, the noise is not linked to pots or input Jack or anything it seems. It would start randomly and stop randomly but slowly got less intermittent and more consistent hence why I felt it could be a component failure on the PCB itself.
Will report back once I've hooked it back up and tested it.
Thanks everyone for their help!
Btw, this Streamer with its Barts and this pre is simply one of the best sounding basses I've ever heard which is why I am keen to get it back up and running!

Edited November 9, 2017 by dyerseve

[Grangur]

If the Bart pickups aren't the originals, then the connections to these is the main place I would look at for poor connections.

[dyerseve]

[quote name='Grangur' timestamp='1510299242' post='3405341']
If the Bart pickups aren't the originals, then the connections to these is the main place I would look at for poor connections.
[/quote]

No they are original and all the connections are fine as I did them lol. I have a reasonable amount of experience with a soldering iron - enough that I rebuilt my valve hifi amp from the ground up without issue, so I am quietly confident in my soldering ability. This PCB is a pig though because by the time I managed to remove it from the plastic housing and then remove all the silicon from the wires and PCB one or two pins for the wire attachements had come loose but maybe they were already loose.

[Grangur]

I hope you've made a record of which wires go to each of the pins in the PCB.

I would doubt the problem was anything to do with that, but good luck with fixing it. Sorry, but I'll withdraw my offer. I wish you all the best. I am an electronics engineer, but there are places I would tread carefully.