Message 27978 in TECH.WW
From: G8MNY
Date: Sat, 15 Aug 26 08:12:00 Z
Newsgroups: TECH.WW
Subject: Rotator Kenpro KR400rc info
Message-ID: <2048_GB7CIP>
Path: N2MH4|N3HYM|IW2OHX|GB7CIP
R:260815/0818Z 35436@N2MH4.#SENC.NC.USA.NOAM LinBPQ6.0.24
R:260815/0818Z 15153@N3HYM.#FRDK.MD.USA.NOAM BPQ6.0.25
R:260815/0818Z 9949@IW2OHX.ILOM.ITA.EU BPQ6.0.25
R:260815/0812Z @:GB7CIP.#32.GBR.EURO #:2048 [Caterham Surrey GBR] $:2048_GB7CIP
From: G8MNY@GB7CIP.#32.GBR.EURO
To : TECH@WW
By G8MNY (Updated Jan 23)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
This is a reliable rotator with manual L & R switches and servo motor driven
different makers. It is almost identical to the KR600, that just has an extra
wire & added motor stop switches.
DIAGRAM __
/Dial\
Motor Common
o = Internal PCB wiring points * = External Terminals
COMPONENT
No R | No R C D Q VR L B
13 10k | 1 220 10n 1N4002 2SC1815 20k 220uH 14V Bulb
14 1k | 2 220 100u 1N4002 2SA1015 20k 220uH
15 1k | 3 10k 100u 1N4002 LM 741 10k
16 390 | 4 10k 10n 1N4002 NMJ4558 500
17 820 | 5 150 10n 1S1588 2SC1815 500
18 47k | 6 150 10n 1S1588 2SC1815
19 33k | 7 560k 10n WZ130
20 330 | 8 560k 10n WZ130
21 10k | 9 10k 100u
22 1k | 10 10k 10n
23 820 | 11 150k 10n
24 5k6 | 12 150k 100u AC
25 2
Common faults..
I have seen on more than one occasion, a split in the plastic pinion on the DC
dial motor. This causes the dial hunting as the display servo can't find the
matching dial pot balance. The cure is to remove the motor carefully slide the
pinion off. Roughen up the D shaped shaft, and using a resin glue, glue back on
the pinion, maintaining pressure across the crack until the glue has hardened,
then reassemble & test.
John G0JOP has had to replace the op-amp on his, I bet this was due to static
or mis-wire on pin 15 straight into the IC! Adding a few k ohm in series with
the inductors L1 & L2 & 4 diodes on inputs to +/- rails may give protection!
A problem Bryan G6ODE found was a loose pinion gear on the motor shaft in the
rotator, that glued up OK as a fix.
Another problem Brian G8VPR mentions is the Rotator Pot going open circuit, so
this the circuit should help do tests.
MODIFICATIONS
I use mine for /P work and have done some mods...
1/ Add a 22R in series with the lamp, to improve lamp lifetime.
2/ Add an 8R 10W in series with motor common on the transformer (*6*) reduces
the super saturation of the motor on 240V 50Hz on low loss leads. As the
motor can work down to 18V with hardly any loss of torque, and for much
3/ Added a 0.47uF 300V AC across the 240V mains, to Power Factor correct the
permanent transformer load.
4/ Keep the pointer screw just loose enough for fine manual direction
adjustment.
5/ Wire colour coded labels and terminal screws.
6/ Heavy duty 6 way plug socket on long lead to ease dismantilling.
Why don't U send an interesting bul?
73 de John G8MNY @ GB7CIP
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