[Collins] Late 51J-4 with strange modification

[Gerald]

On Sun, 2005-08-21 at 13:02 -0500, Mac McCullough wrote:
> Indeed I have had several of these,   and this seems to have been a version 
> made up for a specific customer is my guess,  but yes I have seen and owned 
> several of these ..  although non had or came with a cabinet .  mac/mc
> 
The knob swap could have easily been done by anyone with enough S-line
knobs. Those knobs were readily available within Collins and at Collins
Surplus store in Cedar Rapids during the early 60s. Much of the Collins
surplus stock was sold in bulk to W0MLY and later to Surplus Sales of
NE. All the shafts are standard 1/4" using set screws so any style
including stock mil spec or consumer radio knobs could be applied and
they would function.

As far as I know the serial numbers should have been sequential so the
serial number should have shown the manufacture date or era.

I have a 51J-3/R388 with a light gray smooth panel, the labels are all
engraved except the standby switch label. It has no SN tag, but has a
large round Collins Emblem at that location. There's an early R388 SN
penciled on the chassis rear or the cover. I don't know if this is a
Collins variation or later. Though I'd kind of expect the standby switch
to have been engraved if the panel was modified at the factory.

I recall seeing mostly 51J receivers in the labs and production at Cedar
Rapids in 1963-4. The 51S-1 I saw in 1964 was at Richardson. Its
conceivable that receivers may have been redecorated when used in test
equipment racks so they matched the other custom test equipment.
-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer