FS, Complete UREI/UA LA-3A Limiter Motherboards W/Transformers, Other Components

[David Kulka]

For sale, complete UA LA-3A Limiter motherboards w/transformers and other components. These are surplus fully loaded motherboards that were built by UA for their LA-3A limiter reissue. They are fully populated and assembled, except for the T4 cell and 250K "zero adjust" pot. Each motherboard has a Cinemag B11178B input transformer, UA 22-0018 output transformer, and a step up autoformer for the T4 cell. All resistors, capacitors, and semiconductors are installed, including a Sprague output capacitor and two pairs of MPSU05/MPSU55 power transistors, which are expensive and hard to find. The motherboards are in good, clean condition.

The motherboard is basically ready to go except for the T4 cell and 250K pot. Of course, to build a complete LA-3A you'll also need the enclosure, power transformer, and all the panel parts. (Most of these parts can be purchased from me separately, if you're interested.)

I'll include an original LA-3A schematic but beyond that, I don't really have time to offer any construction or troubleshooting help so after buying, you're basically on your own. That said, the board is very clearly labeled and the circuit is relatively simple, so building a complete LA-3A around this board will not be difficult, as DIY projects go.

Cost is $300 each plus shipping. 7 of these are available, limit of 2 per buyer, please. Payment by paypal, credit card, or check. To buy please reply here with the quantity you want and then PM me with your shipping address so I can invoice you. Thanks!

 

[David Kulka]

Another forum member PM'd me asking for 2 of these, so 3 remain.

The standard LA-3A build used a special 250k linear PC mount pot with a very long shaft, that can be adjusted through the front panel. I can include them for $15 each. But if you mount the pot to the front panel then any type of 250K linear pot can be used.

I'm sorry but I don't have any sort of parts list for the other items that are needed. Basically, you'll need to source an enclosure and all the parts that you see on the front and rear panels of an LA-3A, plus the power transformer, 250K pot, and T4 cell.

AGAIN - if you want to buy, PLEASE reply HERE and mention the quantity that you want. After I see your reply to this thread I will contact you to go over shipping and payment. Thank you.

 

[David Kulka]

Ok , besides the 250K pot and T4 , all other parts can be sub'd in one way or another from off the shelf parts is assumed in your description , right ? no other proprietary parts required , yes ?  ex : special design reverse pots , dual ganged pots etc ?

Correct. With the possible exception of the power transformer (which is also available from me) no unusual or proprietary parts are needed except for the 250K pot and the T4.

 

[David Kulka]

Sorry, duplicate post.

 

[bruno2000]

I'm in for a pair if they are the boards with the Limit / Compress switch.
Thanks!
Best,
Bruno2000

 

[David Kulka]

The motherboards have solder pads for jumper wires that connect the limit / compress switch, which is mounted externally.

 

[bruno2000]

The motherboards have solder pads for jumper wires that connect the limit / compress switch, which is mounted externally.

Great!  Thanks!
I'll stand by my 2 if they're available.
Best,
Bruno2000

 

[David Kulka]

Thanks to all who replied and expressed interest. Later this evening I'll reply to those who ordered, with totals etc.

 

[ilfungo]

Hi David
I'm interested in one pcb...
Available?
Thanks

 

[David Kulka]

The 7 boards have now been sold to the posters above (and 1 more) and I have contacted all buyers by PM. If any buyers back out or if more boards become available, I'll post here again. Otherwise, the offer is now closed.

Thanks everyone, and happy holidays.

 

[wmarden]

Thought it is worth the ask, have all these boards left the building?