[Premium-Rx] Help needed with Harris R-2368 aka RF-590 receiver

[Glenn Little WB4UIV]

If the encoder uses a lamp, it is probably burned out. Common on other 
encoders.
You should be able to replace the lamp.

Glenn


On 10/31/2019 7:15 AM, Heinz Breuer via Premium-Rx wrote:
> Hello to the group,
> I received a Harris R-2368 aka RF-590 this week and turning the VFO knob has no effect.
>
> I just started troubleshooting. My guess I have to start checking the encoder signals which are shaped by Schmitt Trigger 74C14 (U28) and go into Flip-Flop 74LS74 (U22) on front panel board A13A2.
> I see a bunch of tantalum capacitors but none looks burned and other functions seem to work. 5V supply rail is OK. There doesn???t seem to be any chokes in line as Collins did it in the HF-80 equipment where a burned one indicates a shorted tantalum.  On the Control Assembly A14 signals go directly to PIO 8255 and CPU 8055, less likely the fault is there.
>
> Also there are cosmetic issues. One of the front panel handles is badly dented. Obliviously this didn???t happen during shipping to Germany because the box shows no sign of bad handling.
> The back panel got a heavy hit in the past too. It is dented and pushed in around the BNC connectors. Major disassembly and reshaping work ahead unless there is a back plate from a junker available.
> Also the meter dial is flaking off.
> Anybody has a handle or two, back plate from a junker and/or a replacement meter?
>
> In the likely event that the encoder is damaged any idea what could be used as a replacement? How many steps per turn does the original have?  Type number and manufacturer info please.
>
> Is there a service manual available for the R-2368 or RF-590. I have an instruction manual with schematics and board layout but no component data.
>
> vy 73 Heinz DH2FA, KM5VT
>
> Von meinem iPhone gesendet
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-- 
-----------------------------------------------------------------------
Glenn Little                ARRL Technical Specialist   QCWA  LM 28417
Amateur Callsign:  WB4UIV            wb4uiv at arrl.net    AMSAT LM 2178
QTH:  Goose Creek, SC USA (EM92xx)  USSVI LM   NRA LM   SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"