RadioBanter - RS Pro-2021 Info

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Panzer240

January 14th 04 03:45 PM

RS Pro-2021 Info

I have an old RS Pro2021 scanner that I'm trying to resurrect. There is a
lone part on the bottm of the circuit board that is broken. It looks as if it
is an rf choke or perhaps a resistor but I cannot determine what it is or its
value. Is there anywwhere I can find schematics or circuit board layout
diagrams for this scanner on line ?? THe scanner works but has low audio O/P
and the squelch works but not exactly as it should. It seems to be slow
closing after a signal is picked up.

--
Panzer

Jeff Multer

January 14th 04 11:39 PM

the squelch works but not exactly as it should. It seems to be slow closing
after a signal is picked up.

Not uncommon with the Pro 2021.

There is a lone part on the bottm of the circuit board that is broken. It
looks as if it is an rf choke or perhaps a resistor but I cannot determine what
it is or its value.

If it might be a diode, specifically one marked D44 or D45, someone was trying
to extend the reception range of the scanner to include midband (68-88 MHz) and
/ or cellular frequencies.

I have not tried the midband mod, but the cellular restoration mod does not
work ... it only allows you to enter frequencies in that range. The receiver
front end is not designed to receive in that frequency range.

Jeff Multer
Fort Mill, S.C.

Panzer240

January 15th 04 04:52 AM

(Jeff Multer) wrote in
:

the squelch works but not exactly as it should. It seems to be slow
closing
after a signal is picked up.

Not uncommon with the Pro 2021.

thanks for the reply :). The scanner was originally purchased by myself
many years ago and has never been modified for anything. The frequency
range if the unit does not allow for cellular coverage, which is why I
bought something different later on. Very little of any mid band stuff in
my area as well :(.

If memory serves one of the kids or maybe even myself spilled a coke on
it. It (naturally) stoppped working at all. I put it on the shelf and
never got around to working on it until recently. After a good cleaning
and removal of the sticky (even after all those years) residue, it has at
least come back to life. It programs and also receives loacl police and
fire signals as well as aircraft and pager signals just fine. The audio
O/P is a bit low, and when going over the circuit board, I discovered that
the pad on one end of the component I mentioned had broken off the
associated trace and was and open circuit. I cannot identify the part
although it doesn't appear to be a diode, looks more like a 1/8 watt
resistor or perhaps a small RF choke. I would just like to replace it if I
can find out what it is :)

Thanks again for your input :)

--
Panzer

Jeff Multer

January 15th 04 08:46 AM

The following is the parts list still available on the Radio Shack web site, if
you can I-D any part numbers:

http://support.tandy.com/support_ele...oc21/21317.htm

Also, there is a block diagram of the circuit in the manual that I could scan,
if that would be of help.

Jeff Multer
Fort Mill, S.C.

Panzer240

January 15th 04 11:57 PM

(Jeff Multer) wrote in
:

The following is the parts list still available on the Radio Shack web
site, if you can I-D any part numbers:

http://support.tandy.com/support_ele...oc21/21317.htm

Also, there is a block diagram of the circuit in the manual that I could
scan, if that would be of help.

I have the User manual and have looked at the parts list. Unfortunately
this part is on the underside of the circuit board. In fact it is the only
visible component when you remove the bottom cover. (Located in approx the
center of the board) Unfortunatley there are no Identifying marks on it or
on the board. That's why I was looking for the schematic and/or a pc board
overlay diagram.

Thanks again for your imput.

--
Panzer

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