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U.S. Peavey Club

#5,541
Hi guys, longtime Peavey fan here. I've owned a Foundation (1st quality bass bought back in '89), a Sarzo, 2 Cirrus 6ers (fretted walnut and fretless redwood) and now have a TL-6.

I bought the TL-6 used here on TB and the bridge pup isn't producing any sound. I've done several searches (with no luck) trying to find the wiring diagram. I have suspicions that a previous owner may have messed around with the guts on this bass because 1) the black plastic p'up covers have string gauge marks in them but they don't line up with the strings... like maybe the pickups were swapped (bridge for neck) or the covers at least were swapped. 2) There seems to be no p'up selector knob or switch.

Here's what's going on: The active EQ (3 smaller knobs) works, the switch is an active/passive switch, the treble becomes a tone in passive mode, the large knob closest to the bridge has a center detent and has a very faint affect on the sound of the bass. Is this a mid shift knob?? It seems to have an affect in BOTH passive and active mode although it seems VERY minor in passive (confusing!!). The large knob closest to the neck is volume. NOTHING I do with any knobs or switches will get the bridge pup to produce sound.... I'm doing the tap a screwdriver over the poles method :D... nothing :hmm:.

Any help will be much appreciated!! I took it to a tech yesterday and he said he wouldn't troubleshoot it because of the preamp. He's more of a passive instrument troubleshooter and setup guy. So, for now it's on me to figure this out.

Thanks,
JJ
 
#5,542
Here's a pic.
ImageUploadedByTalkBass1370706925.085603.jpg
 
#5,543
JEDI BASS said:
Here's a pic.
View attachment 342215
Click to expand...

Wow sweeet bass !!!

Here is my suggestion - First, I believe the TL's / Dyna's / Sarzo's all used the same preamps, but I'm not sure..... I know even the Axcelerator wiring was like a rat's nest and it is simple compared to the TL/Dyna.

So, if you can't fix it, I'd buy a $300 Dyna and swap out the preamp and out it in your bass. Sometimes we just have to resort to other old Peavey basses to get the job done. I've seen people take the coveted T40 electronics and put them into a different and Lighter bass. Plus, it's just fun !!! I have a custom with Cirrus electronics in it and I modded a Kawai FIIB with all Cirrus electronics and it sounded 1000x better than the original.

Mike
 
#5,544
JEDI BASS said:
Hi guys, longtime Peavey fan here. I've owned a Foundation (1st quality bass bought back in '89), a Sarzo, 2 Cirrus 6ers (fretted walnut and fretless redwood) and now have a TL-6.

I bought the TL-6 used here on TB and the bridge pup isn't producing any sound. I've done several searches (with no luck) trying to find the wiring diagram. I have suspicions that a previous owner may have messed around with the guts on this bass because 1) the black plastic p'up covers have string gauge marks in them but they don't line up with the strings... like maybe the pickups were swapped (bridge for neck) or the covers at least were swapped. 2) There seems to be no p'up selector knob or switch.

Here's what's going on: The active EQ (3 smaller knobs) works, the switch is an active/passive switch, the treble becomes a tone in passive mode, the large knob closest to the bridge has a center detent and has a very faint affect on the sound of the bass. Is this a mid shift knob?? It seems to have an affect in BOTH passive and active mode although it seems VERY minor in passive (confusing!!). The large knob closest to the neck is volume. NOTHING I do with any knobs or switches will get the bridge pup to produce sound.... I'm doing the tap a screwdriver over the poles method :D... nothing :hmm:.

Any help will be much appreciated!! I took it to a tech yesterday and he said he wouldn't troubleshoot it because of the preamp. He's more of a passive instrument troubleshooter and setup guy. So, for now it's on me to figure this out.

Thanks,
JJ
Click to expand...


That is the first generation Dyna Bass Pre. You will have to contact Peavey to get the schematic, they should email it toyou within a few hours. They have great customer service.

The bigger knob by the bridge is the pickup blend, the bigger knob towards the neck is the volume.

If you have a multi-meter, Remove the nuts and washers from the pots and switch and carefully lift the pre out of the cavity, its a tight fit. find the wires for the bridge pup and see if you have signal when you touch the probes to the ends of the bridge pup wire. If you have signal, you may just have a colder solder joint on one of the pot connections. If you have no signal, then they are most likely dead and you need to find new pups. you may be able to test the leads at different points to see if there is a break in the wire or examine the pups to see if the wire is separated from the bobbin. If it is, you might be able to drop a bit of solder on it to repair them.

Let me know if you need anything else.

If you were closer to me I'd say bring it by and we'd take care of it today!
 
#5,546
mb94952 said:
Wow sweeet bass !!!

Here is my suggestion - First, I believe the TL's / Dyna's / Sarzo's all used the same preamps, but I'm not sure..... I know even the Axcelerator wiring was like a rat's nest and it is simple compared to the TL/Dyna.

So, if you can't fix it, I'd buy a $300 Dyna and swap out the preamp and out it in your bass. Sometimes we just have to resort to other old Peavey basses to get the job done. I've seen people take the coveted T40 electronics and put them into a different and Lighter bass. Plus, it's just fun !!! I have a custom with Cirrus electronics in it and I modded a Kawai FIIB with all Cirrus electronics and it sounded 1000x better than the original.

Mike
Click to expand...

There are two different pres that were used, the 5 knob with the active passive switch (1985ish), and the 4 knob with the stacked low/mid and high/mater tone with the switch (1991ish).

Personally, I think the first generation sounded better and was a better layout.
 
#5,547
Thanks Texan, the reason the large knob near the bridge baffled me is that the bass still has volume no matter how I turn it. So if its a pickup pan, then why does the neck pup produce sound all the time while the bridge pup never does.

Maybe both the br pup and the pan pot are shot???
 
#5,548
JEDI BASS said:
Thanks Texan, the reason the large knob near the bridge baffled me is that the bass still has volume no matter how I turn it. So if its a pickup pan, then why does the neck pup produce sound all the time while the bridge pup never does.

Maybe both the br pup and the pan pot are shot???
Click to expand...

Before assuming the pickup is dead, i would check the wiring. Sounds like the bridge pickup may have disconnected from the pan pot. if that's the case, should be an easy fix.
 
#5,550
JEDI BASS said:
Thanks Texan, the reason the large knob near the bridge baffled me is that the bass still has volume no matter how I turn it. So if its a pickup pan, then why does the neck pup produce sound all the time while the bridge pup never does.

Maybe both the br pup and the pan pot are shot???
Click to expand...

Possibly, but it sounds like the blend may be wired wrong.

Verify that you have continuity on the bridge pup leads and that will tell you which direction to go. If you have continuity, I'll bet you my mother in law that the blend is wired wrong or shot.
 
#5,551
JEDI BASS said:
I'm hoping for an easy fix. But like I said, the neck pup is always on so....
Click to expand...

Right. That's what makes me think the bridge pup has disconnected. With a bass with blend, both pups are connected to the blend pot before the volume pot, so if the neck pup is connected, it should stay on at some capacity until the blend is all the way counter-clockwise, which would be 100% bridge pickup. if the neck pup volume is on full from the center detent and all the way clockwise, it's working properly. Should start losing some volume when turning the blend counter-clockwise.
 
#5,552
Texan said:
Possibly, but it sounds like the blend may be wired wrong.

Verify that you have continuity on the bridge pup leads and that will tell you which direction to go. If you have continuity, I'll bet you my mother in law that the blend is wired wrong or shot.
Click to expand...

NicJimBass said:
Right. That's what makes me think the bridge pup has disconnected. With a bass with blend, both pups are connected to the blend pot before the volume pot, so if the neck pup is connected, it should stay on at some capacity until the blend is all the way counter-clockwise, which would be 100% bridge pickup. if the neck pup volume is on full from the center detent and all the way clockwise, it's working properly. Should start losing some volume when turning the blend counter-clockwise.
Click to expand...

You guys are great! Very helpful!

I think Clay (Texan) has nailed it though. There's no real loss of volume from the neck pup when I turn the pan pot all the way in both directions, even though there is a very small change in tone.

First step will be to test the br pup w/ my meter to see if it's functional. Clay's gonna make sure I do that right via PM :). Then I have to figure out what's up with the pan pot: check it's functionality and solder joints etc etc until I nail down the issue.

I'll keep you guys updated and THANKS again for the help. It'll be later tonight or tomorrow before I can dig into it though since I have plans w/ the Mrs.
 
#5,553
4001Chaser said:
A question about the Koa Unity basses. I played one a friend had some years back and it is the reason I have my Dyna Unity now. The sound and feel had me hooked in an instant. However, the Koa was extremely light weight.....and beautiful..... and my back would love it but, it really had "neck dive" problems. Is this an issue with all the Koa Unitys and how do you compensate for it? Yeah, I want one of these too. Thanks!
Click to expand...

Only had mine a couple of days, but I've been playing it a lot! :D

I use a 3" leather strap and find the bass just a little neck-heavy. Really, though, it's minor enough that I hadn't even noticed it until you asked. That body is seriously light, though...

Speaking of straps, if anyone is looking for a quality leather strap and wants to support an honest-to-goodness, locally-owned, mom and son small business, check out Invalid Link Removed. No affiliation, but they do great work at a very reasonable price.
 
#5,560
JEDI BASS said:
....I think Clay (Texan) has nailed it though. There's no real loss of volume from the neck pup when I turn the pan pot all the way in both directions, even though there is a very small change in tone.
Click to expand...

Note that the pan pot in the 5 knob Dyna type preamp is not a true pan pot. It's a single element 50K Linear with the pickup outputs coming in on either end and the "blend" taken from the wiper. With everything operating properly, there will always be a little signal bleed from the pickup not selected. If one pickup is open or not wired to the circuit, the blend control will just reduce the volume of the working pickup slightly.

My swag (scientific wild a$$ guess) is the same as Texan's. That the wiring for the bridge pickup is at fault or there's a cold solder joint. Less likely is that the pickup is open.

When you look at the solder pads for the wires, there are letters by them that stand for what connects at that location.

N = neck PU hot
B = bridge PU hot
G = Ground
+ = battery positive
- = battery negative
R = jack ring (battery switch)
O = output

The trim pot is for setting the output balance between Active and Passive modes.

DynaBassPCB-foil_zps90cbdd40.jpg


Just for fun facts...rdg is the preamp engineer, FJE is the circuit board designer, DYNA BASS the product name, 98890361 the raw circuit board part number and 072385 (July 23, 1985) the date code for when the circuit board artwork was finished (for this revision). The artwork for the circuit board pictured was laid out by hand. There's at least one later version that was computer generated with a date code of 020588 and PCB designer initials WM from the time Peavey transitioned to computer circuit board design. There's no real difference between the different versions.

mech
 

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