Series I 75-150

[jazzyvee]

Hard to find, so bumping it further up the line so the lost an find it easier

it would be interesting to see how far and wide his basses have scattered.  i myself own a fine specimen of his that i dance with almost every day.

Well mine is in England UK.

[jon_jackson]

Two in Kansas, USA

[dela217]

I am wondering who ended up with 75-219?

[rv_bass]

I am wondering who ended up with 75-219?

Me too, that’s another nice one.

[captain_jan]

Hello all,
Some time has passed but as I promised last year I'd post some pics of the beautiful 75-150 which is now at my home. As you can see the missing logo was never found, the seller didn't find it anywhere. Another more annoying issue is the treble pick up is dead when the bass is connected to the normal cable & plug. But when trying to use the 5-pin AC adapter plug & cable there is a loud disturbance signal coming form the bass and nothing else. So no playing. This means I must get the bass over for a service later this year.[/size]
If you have any special advice when sending overseas instruments for a service at Alembic (US customs etc) please let me know. Also some preliminary quote for an electronics overhaul plus the logo installation would be great to get. But nothing should be done to the varnish finish, she looks great in this weathered appearance.
The 75-150 is pictured here together with the 75-143 (which is a double serial number) and the AM-106.
brgds
Jan

[rv_bass]

Beautiful bass! 

The 1/4” jack is likely stereo, so you will need a stereo to mono cable to hear the treble pickup when using the 1/4” jack.

Try exercising the toggle switches and volume and filter control knobs.  Flick the switches back and forth 50 times each.  Turn the control knobs back and forth all the way 50-100 times and see if that helps get rid of the noise.  There are also trim pots on the back so see if you can dial out the noise.

[rv_bass]

Duplicate

[edwardofhuncote]

I wonder if there may be an issue with the voltage on the DS-5 where Jan is?

It's a good sign the neck pickup functions well under battery power. Here's another easy checkup - plug a set of stereo headphones into your 1/4" jack and see if both pickups and selector switch are functional.

Agree with everything else Rob posted; exercise the livin' daylights outta' those old pots and Q-switches.

Great to hear from 75-150 again... that's one of my all-time favorite Alembics!

[captain_jan]

Thanks for your answers. My power supply is working well on my other Series I and II basses and voltage in Switzerland is the European standard 230V. I must try this stereo headphones trick once I am back home. The disturbance sound was really loud and no other signal came through, will exercise the controls as per your advice to see if it would make any difference. But my bet is I need to ship her over for some proper checks?
Best regards from the Gulf of Thailand
Jan

[mica]

Confirm the pickups are all seated well with their connectors. Also make sure the humcanceller is plugged in the middle.

[captain_jan]

Dear Mica & everyone,
Thanks for your replies. I opened the back but could not see anything loose inside and all cables looked ok to me. I plugged the bass in again via the DS-5 and moved up and down all controls several times as instructed. The bridge pick up is alive but the signal is very weak and if the string is plucked a bit harder the signal becomes distorted. Also it is accompanied by a very high pitch tone when switching around with the Q switch or when pressing lightly at the 5-pin connector plug. The neck pick up works fine with a proper signal strength.
So there is something wrong, maybe trying to get a local workshop to have a look unless you have a better option for a service? No idea if I can trust such an instrument to someone who has not been working with vintage electric guitars.

[rv_bass]

You might try turning the knobs and flicking the switches a couple hundred times each, I had to do that once on one of my basses.  Also make sure the 14 pin ribbon wire connector is connected securely.

[rv_bass]

And try switching the pickup connectors on the board to see if both pickups are working in the neck position and if both do not work in the bridge position.  That will tell you if it is the pickups or the board/something else.

[JimmyJ]

... try switching the pickup connectors on the board ...

That's the next logical troubleshooting test.  I think you have the old mini-coax connectors so you will need work a bit to be able to disconnect them.  Here's the explanation:
http://alembic.com/club/messages/16271/25011.html?1139618837

The idea is to swap the blue and the red connectors, then power up the bass and see if the bridge pickup appears loud and clear in the neck pickup channel - and the neck pickup is now sounding weird.  If that's the case it points to a problem on the board.

If you are able to try that please let us know what you find.  Then we can help you figure out your next move.

Jimmy J