| Author | Message | ||
| jet_powers
Advanced Member Username: jet_powers Post Number: 306 Registered: 2-2003 |
I recently had to replace a volume pot on my 85 Persuader. Mica told me that a direct replacement was not available so I would have to replace it with a new model and would also need to replace the other volume pot with a pan control leaving only the filter. In the process of replacing the pot I stupidly destroyed the filter and had to replace that as well. The new controls do not seem to work as they should. i.e. there is no master volume and the filter control does not seem to do as much as it should. (you don’t get that ’wah’ sound when turning it.) Point to point connections of the parts were checked before and after, and there were no abnormalities. Does anyone know of any schematics that are available or can tell by looking at the picture if something is not right?  | ||
| bsee
Senior Member Username: bsee Post Number: 1404 Registered: 3-2004 |
With regard to the filter wah effect, that is a result of the Q switch boost value. On a bass with a Q switch, the wah effect only occurs with it in the "on" position. I believe the standard setup for a filter with no switch is to have an 8bB boost hard-wired. Is it possible that your replacement filter was set up with no Q boost? | ||
| jet_powers
Advanced Member Username: jet_powers Post Number: 325 Registered: 2-2003 |
Time to revisit this one... I did not mention previously that the filter control has a center detente in it. You know, the thing you would normally find in a pan control to let you know when you are in the center position. It does, in fact, function as a filter. The other two pots are functioning as volume controls for their respective pickups. In other words, it functions the way it did before the controls were replaced. Not necessarily a bad thing. However, I was under the impression and also desired that the new controls were going to be for a single volume control with a filter and pan. I thought that perhaps scematics would allow for a proper point to point check but I don't think that's the issue here, but I'm no tech. Any thoughts on this? -JP | ||
| mica
Moderator Username: mica Post Number: 4451 Registered: 6-2000 |
Filter controls don't have a center detent. The part number on the back of the filter pot should read 475-021. If it differs, we need to get that repaired. Was this something you purchsed new from us? The two pickups should be plugged into the pan module - it looks like you have one pickup going to the volume control and the other to the pan. Once you straighten that out, you'll be in good shape. Let me know! | ||
| jet_powers
Advanced Member Username: jet_powers Post Number: 326 Registered: 2-2003 |
Thanks for the response Mica. As for your question, yes all the pots were purchased from Alembic last fall. Currently 475-021 is functioning as the bridge pickup and is the the pot at the top of the above photo. 475-020 is the neck p/u and shown at the right with 475-025 functioning as the filter but which I suspect should be the pan as it has the detente. I can't tell from the photo and without opening the back of the bass it's dificult to see how I would connect into the pan module. If I understand correctly I should plug both 020 and 021 into 025? Should there then still be a connection between 020 and 021? This is probably something very silly and I apologize in advance for my technical ignorance. JP | ||
| mica
Moderator Username: mica Post Number: 4456 Registered: 6-2000 |
Here's how the connections should go: both pickups into 025 (2-pin) 025 to 021 (2-pin) 020 to 021 (3-pin) But after reading that you replaced the volume pot with a pan pot, and reviewing the items you purchased last year, I think there was a misunderstanding. You don't only have to change the pots - you need to replace the original 2-volume harness with a 1-volume harness and a pan module. Here's what you the parts should look like:  I think the best thing is to send the electronics in for servicing. We'll be able to install the filter pot on the filter module and the pan control on a pan board to make a pan module since you've already paid for these new pots. We'll also put the volume pot on a 1-volume harness (and you'll get a nice new and improved jack to boot). Call or email me to make the arrangements. |
