OBSERVATIONS FROM SCOTLAND 28 May 2008 GM1SXX
My 'new' RA1720 Arrives.
The MA1720 arrived today, with a little help from EBay. It arrived with the right side rear (steel U
section) chassis bent and the right side (ally) front panel somewhat bent and
the grab handle on that side distorted. This is not a problem for me.. I can
easily straighten them out in our workshop out but it's a nuisance. I did
inform the seller, just so he knows it arrived bent, BUT I don't think there was
any problem with the packaging. Looks like the carriers were a tad careless to
me.
On a positive note, it worked perfectly straight out of the box, the build
quality is typical awesome RACAL and I'm very happy with my purchase. I liked
the graffitti I found inside ... Pete was 'ere, a nice personal touch!
In the antiques trade, that's called 'provenance'. I sometimes watch
'antiques roadshow'. I suspect the dented steel panels might also fit the bill.
I'm truly amazed. I cut off the old (obsolete) BULGIN type mini-connector
(ouch!, some 'provenance goes out the window!) and wired
the mains straight to the turret tags. I put 4 Ty-Wraps on the cable so it can't
be ripped loose. Some ohms checks and I was ready for the big 'KABOOM' test.
Plugged it in, flipped the switch.... and voila... the protection tripped out!
No RF. Just a big bright red indicator saying RESET!
More messing showed that I was doing it wrong. I have a rock steady carrier on
any freq I choose from DC-30Mhz (in 100Hz steps).
Despite being bashed around by the couriers to the state where the steel side
cheeks (1.5mm steel plate bent into a U channel!!!) got bent and the front panel
twisted... the damned thing delivers 20 or 200mw of RF as advertised!
Here's to Pete! He seems to have done a good job of caring for this beast. I
notice that sudden BIG frequency jumps (on the decade switches) can make the
synth quit and the reset circuit fire ... but you'd NEVER get that in a real
situation, AND its VERY obvious when there's no RF and a big RED Indicator.
I need some replacement lamps... for the Synth 'LOCK' and 'reduced power'
indicators but other than that, it's ready to rock & roll.
For the next trick... I'll attach it to the RA1772 which it's sitting on top of,
and slave the receiver synth to the TX strip. Like the RA1772, the panel meter
does a million things. It monitors ALL the power supplies.. +5, +12, +20, -7V as
well as being a wattmeter, RTTY monitor and a few other things besides (that I
aint worked out yet). The build quality is second to none. In fact it's even
nicer and neater than the RA1772. It MUST have been built b4 the bean counters
moved in and wrecked the company. No expense is spared. The main filter caps are
rated at 10 amps ripple current. Hell, it's only a 'little 200mw TX Exciter!
Hopefully some photos tomorrow.
MA1720 links
radiomuseum.org Transmitter_drive_unit
More as it happens.
73 Al.
GM1SXX
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