[Hammarlund] Re: SP-600 Question

[Albert Solway]

"James A. (Andy) Moorer" wrote:

> ----- Original Message -----
> >You should put a 'scope on the power supply sometime. It is quite
> interesting - the power supply voltage waves up and down by several (!)
> volts depending on the signal (!!)

> Will do. Should be in 4 or 5 months.

> I have an R-390 that I replaced the 26Z5's and 6082's with a solid state
> rectifiier and voltage regulator. I did not know what the load current was.
> One of the guys on the R-390 reflector indicated that it was about 130MA. I
> measured between 120 MA and 155MA depending on input signal level. High
> signal, current is about 120MA. Antenna disconnected (low signal), current
> about 155MA. I think this is because of the AGC action. Low signal, AGC
> voltage is low. Result is all tubes under AGC control are conducting harder,
> therfore load currnet is high. The reverse is true with a high signal.
> Little change in O/P voltage, which indicates that the regulator is working.

> I wonder if the SP-600 voltage regulator has problems  compensating for load
> current fluctuations. This would explain the voltage swing. What do you
> think or am I all wet in my assesment.

>
> > Also in a previous post I indicated that L52 had been overheated and
> > that the bottom cover had partially separated from the case. A follow up
> > question. The inductance of  L52 measure 30HY, required is 20HY. L51
> > measures 9.5HY, required is 8HY. Comments please.
> >
>
> Those values are well within bounds. In general, the more the better. The
> cores of those things are made of many iron leaves just pressed together.
> Sometimes after 50 years they fuse a bit which may cause the inductance to
> rise. I don't see any cause for concern unless the resistance has gone up
> sharply. That would indicate frayed or cooked wire to me. Although these
> inductors are pretty sturdy, I have seen them open, but I have never seen
> one that was marginal - it either worked or it didn't.
>
> I might ask how you measured the inductance.
>

I have on old GR650A Impedance Bridge with the 650-P1 Oscillator-Amplifier.
Seems to work OK but has not been calibrated since 1973. I measured about 50
capacitors and resistors and the average error is about 3% low..

Does anybody have or know of a calibration procedure source for this bridge.
The manual only gives maintenance instructions not calibration. The manual
shows calibration adjustment screws only.

>
> Hope this helps.

Sure does and thanks very much.

Have a good day

Al