Interesting Pro 2004 Problem(duplicating frequencies)

[TeRayCodA]

Picked up another 2004,when entering freq,in ch01,it will duplicate the same freq into Ch03.
Programming freq into Ch02 will duplicate to Ch04,and so on......But only in pairs of two!

The 9V memory retention battery was removed for some time,before it was given to me to work on.

I have used the reset/on/off,clear,restart,removing the battery,unplugged radio ,ect.

Some mods were done,as I have returned everything back to the factory condition.

Anybody know what this could be?(aging electronics?)
Everything else works fine.
My other 2004 works fine.
May need to look at some of my Bill Cheek troubleshooting books.

 

[Chris-M]

re: wacky PRO-2004

I'm hesitating to interject anything regarding your problem because I'm not an 'edumuhcated' electrical engineer/ra-did-eOH tech. Yet I do have a 2004 and the repair manual for it right here. :lol:

There is nothing in the 'troubleshooting' section regarding your prob.

However it does say under Priciples of Operation, and this is my interpretation, that 'any unstable supply voltage to the CPU (IC-503) can produce CPU manfunctions such as wrong data processing, wrong data transfer, etc. To overcome this, C512 and R501 "initialize" the CPU. Initialization is accomplished when the RESET switch is pressed." The manual does have examples of an 'initializing' waveform. I do not have the knowhow nor the technology in my shack to read said 'waveform' even if I had the same problem that you do. My uneducated guess is that the CPU is not getting the correct voltage to pin 28.

What I would do if it were my scanner is get a copy of the Realistic Service Manual part number 20-119/9119 for the PRO2004 and take it and the scanner into a knowledgeable radio/scanner techie.

I bought my service manual on EBAY recently just in case my 2004 starts to show it's age.

I hope that helps. Sorry I can't tell you why it's doing what it's doing!

 

[TeRayCodA]

Thanks;Chris
It really is not a big problem,as I am only using this one for mil-air,and the duplicates don't really bother me.
Everything else works great.
(this is an early model,circa 1987,so,it is a little different on the inside of my later one)
Thanks.

 

[fineshot1]

Its possible one of the Pro2004 radio mods that you put back to normal was one of the memory mods that have been published over the years.
I dug up the info below on the internet. I think there was also another memory mod that added a complete new memory module but I have no info on that one. Hope this helps......dan

These mods are detailed in the following articles:
a) POPULAR COMMUNICATIONS AUG 87, PP 18-20
b) MONITORING TIMES OCT 87, P 53
c) MONITORING TIMES DEC 87,P 60
I suggest strongly that you obtain the back issues and read through the letters or articles. I also suggest you subscribe to the mags. They supply a lot of great info and freq lists. Now the mods.


400 CHANNEL MOD !
1. Remove the four screws from the back of the radio, and slide
off the cover from the chassis.

2. Turn the radio upside down. You will find a metal box-like sub-
chassis in the center of the main chassis. Remove the cover and
you will be looking at the CPU, a 64-pin integrated circuit.

3. Examine the component side of this board, and you will find a row of
diodes and resistors. On one end of the row you will find a diode
labeled D-513.

4. On the top of the sub-circuit board, locate the slot for D-513. Count
backwards from there until you get to the space for D-510. Install a diode
at D-510 in the same polarity as the rest of the diodes. There, you now
have 400 channels instead of 300 ! Carefully re-assemble the metal box.
Make sure everything else is as it should be. RE-invert the radio so it is
right side up.

 

[Chris-M]

I did the extra channels mod to my 2004 years ago, and it doesn't exhibit the problem mentioned above.

Each of the 10 banks has 30 channels. The mod adds 10 channels per bank. It's an easy mod that is worth the extra 100 channels.

 

[fineshot1]

Clarification to 2004 memory problem post

To: Chris-M
I did not mean that " the mod " itself caused the symptons he described.
He stated that he removed some mods in his original post and my suggestion is that he possibly made a mistake in removing one of them that is related to any of the memory mods published over the years. That is my suggestion.

 

[TeRayCodA]

Well,as of this post,about an hour ago,the CPU must have freaked out,and I heard a radio station playing on 107.XXXx. -the scanner lost all memory!

I reprogrammed it back,now everything is as should.Direct search works,no duplicates!

Could it be that this radio has been without AC power for so long,that something needed to build up,or energize?
Geez,idunno!

One fellow I know of has had his to unlock all banks at once.(radio phantom strikes again)

I am looking at ordering a new IC-9 regulator(most always gets bad with age,according to the late Mr.Cheek),to replace in this oldie-but-goodie with the newer stock #?

anybody order one lately?
Thanks!

 

[pro92b]

The output of IC9 should be 5 volts with the radio unplugged and a 9 volt battery installed. If it is 5 volts there is no need to replace it.

You can swap some of the boards between your two PRO-2004's to isolate the problem if it returns.

Intermittent problems like yours are often due to quality problems with the circuit boards in the radio. See http://www.radioreference.com/modul...e=viewtopic&t=18346&highlight=pro2004 for more info.

 

[TeRayCodA]

Thank you;Everyone
I am in the process of "touching up"the circuit boards.I just got the CPU board done,(doing one board at a time,and running it a while)-some success.-it is acting like it will retain the memory better,but only time will tell.

 

[TeRayCodA]

Ok,I have re-soldered the board next to the CPU,and have been running the 2004 for two days now.And everything is working flawlessly!

Now, I am just waiting for my new backlight to come in!

Pro92b;your info about the circuit boards is invaluable! Did exactly as you said.

Thanks again for the tech advice,it's folks like you that keep these forums worthwhile! :wink:

 

[TeRayCodA]

Just installed the new backlight,and it really livens up the display!