AR2002 Issues

[KK4HG]

I have one of the subject radios that seems to have developed some sensitivity issues especially in the lower frequency ranges: 450mHz. on down. However, the problem is not consitent throughout the bands. For example, I am now listening to local Bristol, VA police on 155.590 but I cannot listen to 155.490 which is also a local SW Virginia police dept. Also, when keying on 146.52 on a radio right next to the RX, the squelch will not open on the RX even though it is tuned to that freq. Actually, sometimes the squelch will open but what comes out is uninteligible but sometimes a portion of the repeater squelch tail can be heard.

I have also noticed as the day has worn on that the squelch control is becoming more and more less effective. I have had to apply more and more gain for it to become effective.

I have called AOR and they no longer support this radio because of parts availability (or lack thereof). Taka at AOR told me that the problem is probably with NEC chip MC5800 which is 6 pin low band amplifier.

I guess what I am trying to ask here is does anyone know anyone thqat can repair this RX or perhaps a source or cross reference for the chip?

EDIT: I forgot to request a schematic and parts list with circuit board layout...anybody?

EDIT: I found a service manual and schematic. Also have a better discription of the required IC: It is a hybrid, wideband amplifier IC.

Any help would be greatly appreciated.

 

[EddySand]

Mc-5800

Sir,
The MC-5800 was a custom-made NEC IC that was used in a lot of mid-1990s scanners. They are completely unavailable and have disappeared from the planet and there is no cross reference. I have had the same thing happen to one of my AR2002 and an Icom R-100.

I would advise finding another AR2002, because you woun't be able to repair yours. In terms of basic RF performance, the AR2002 is one of the best ever made, but it's scan functions are rather primitive.

Hope this helps, Eddy

 

[KK4HG]

Thanks, Eddy. After an exhaustive search, I was able to find a source for the MC5800 in Japan. They are rather expensive but available non-the-less. If you still have an AR2002 that suffers from this malady and want to sell it, please let me know. That goes for anyone else out there as well!

 

[EddySand]

MC-5800 Source

Hi Again, 4HG
A lot of the mid-1990s Regency scanners were made by AOR, such as MX5500 and MX7000. The all have the MC-5800 RF Ic, and usually sell very cheaply. Also, same-era ICOM scaners like the IC-100 have them.

Can't say I want to part with my AR-2002, it's too good of a single-frequency receiver!

Eddy

 

[KK4HG]

Thanks again, Eddy for your timely input. The radio is now at a local repair shop so we'll see what happens. If need be, I may go ahead and purchase one of the $68.00 MC8500s I found in Japan...hope not though! I will also keep my eye out for MX5500s and MX7000s...thanks for that tip.

 

[KK4HG]

Just thought I would let you know that an allignment is all the radio needed. It is now working as designed!!