My rare "Alembic"

[sonicus]

Dave , These five names  appeared in my mind ; Rick Turner,  Frank Fuller. Michael Dolan, Doug Irwin , Larry Robinson.
 Perhaps one or more of these craftsmen.

[adriaan]

Here's an earlier thread from 2005!

[David Houck]

I knew I had seen that headstock before!  Thanks Adriaan!
 
Wolf; in the thread Adriaan points to, Michael suggests Bruce Becvar.

[sscastro]

Hi Dave
 
the bass only sounds out of 2 positions. There's also no stops so the switch goes around in circles. It's always noisy. I will get pictures of the connections and I will try to identify which wires come out of which pick-ups.

[sonicus]

Oh yes, Bruce Becvar!   Thanks .

[lidon2001]

ss, both outputs are normally stereo.  You would have to get the proper 1/4 cable to hear both pickups.

[David Houck]

Sergio; I thought you said you had a new switch in place.  Is the new switch going around in circles?
 
The four positions are neck pickup, both pickups, bridge pickup, and standby.  The standby of course should not have sound.
 
I'm wondering if the position that doesn't have sound, but should, is either the neck pickup only position or the bridge pickup only position.  And I'm also wondering if you put the selector in the both position and then turn the volume knobs for the two pickups, is one of them not making any sound.
 
Determining the above may help narrow down where the problem is.

[David Houck]

Thanks Tom; I missed that when reading his reply.
 
Following up on Tom's point, are you playing through the IN-2 with the 5-pin cable, or are you playing through the 1/4 jack with a standard guitar cable?

[sscastro]

At the moment I do not have the IN-2 here with me, so I was going through a standard guitar cable, and you are right it should be a stereo one, even if ring and tip are soldered together, otherwise I was shorting one of the pick-ups. When I fitted the new switch I missed the stops, hence it goes round in circles. What I found some minutes ago, trying to make pictures from the connections is that there is an earth flat copper foil, glued to the bottom of the cavity, connecting the back plate, and to the switch. But it does not get there, as it is completely smashed and rotten. So I wonder if by making a piece of stranded sleeve going from the pots chassis to the switch chassis, the noise will simply go.
I will try all your test recommendations, but I need new batteries also, as they are quite weak.
thanks everyone.

[David Houck]

Sergio; the Series electronics run through batteries quickly, so getting your IN-2 and using that will be helpful.
 
And yes, the quarter inch standard cable may be the reason sound was only coming from two positions.  Simply soldering ring and tip together is not sufficient.  Instructions for making a good cable can be found here.
 
The pots are grounded to the shielding; so yes, if there is a problem with your shielding, that may be the source of the noise.  You can purchase shielding paint from Stewart-McDonald and other sources.  The shielding should be repaired as it protects the electronics from RF noise.

[sscastro]

Hi dave
 
I took your advise and looked into the connections of the jack and all is according to stereo 1/4 wiring:  
On the grounding flag wiring all seem right too if black to harness means to pins 1 and 10 together on the selector switch, which is what I've got. Definitely I can't get the bass pick-up on its own, but I have them both after the bridge pick-up position.
Another interesting point is that not all pots connect to ground. Bass pick-up volume pot does, but treble volume pot does not, both treble EQ pots are linked, but on the bass EQ only the first pot (closer to the knob) is linked. Also only one of the switches seem ground linked, the one amongst all 4 pots. By the way are they doing exactely the same, one for the bass one for the bridge pick-ups. I believe it's passive, active shelving and parametric. Could you please let me know?

[slawie]

Sergio would you be willing to part/sell off the IN-2 only?
Is it voltage capable for Europe i.e. 240V?
 
slawie

[David Houck]

Sergio; the entire control cavity should be painted with shielding.  The shielding is the ground.  When a pot is firmly attached to the body of the instrument, it is grounded to the shielding.  If a pot is loose, the connection to ground is broken.
 
The controls for Series I electronics are described here.  It is all active.  And yes the setup for the neck pickup is the same as for the bridge pickup.  Each pickup has a volume control, low pass filter control, and a Q switch, all described at the link above.
 
If you do not have a stereo 1/4 cable as described in the link in my previous post, you will not be able to hear both pickups.  However, what you may want to try is to plug a set of headphones with a quarter inch stereo plug into the 1/4 stereo jack on the bass.  If the bass is working properly, you will be able to hear the neck pickup on one side of the headphones and the bridge pickup on the other.

[sscastro]

Hi David I will be away for a couple of days, in Portugal, but I'll get back to this. Definitely there must be something wrong on the connections. If the shielding is effective to the pot attached to it, should be so to the second pot on the bass EQ. In the meantime I found the controls description in your previous link and now I understand it better.
The headphone test, wasn't easy as I only use studio 600 ohm sets, but I was still able to hear something and both pick-ups are there. So one position is bridge pick-up on the Right side, the next is in the centre, or thereabouts, due to frequency differences, the next is neck pick-up on the Left and then silence. The 3 other positions ARE noisy, and it sounds like a lack of ground. I will investigate where its broken and maybe I will need to hard wire the pots which show no ground connections. Do you think it's a good idea?
 
Sorry Slawie, for the time being I am not willing to sell the IN-2, and yes it is for 240V. I have another small power supply, which is definitely for 115V. I've never used it before because of that.

[David Houck]

Good; sounds like you're getting both pickups.
 
No; I don't think you need to hard wire the pots if they are snug against the shielding.
 
At this point, good quality pictures of the interior of the control cavity and of the selector switch may be helpful.