Need help with a Technical Question!!!!!

[N1SQB]

I am in the process of modifying one of my scanners to make it scan faster. Now the mod calls for a
"quartz microprocessor crystal" of a higher value. My local electronics dealer sells "quartz crystals". The problem is this, is there a difference in the 2? He has no idea what if any difference there is. Can anyone help here?????? They are only $6 each but the drive is 30 minutes one way and nobody else closer has one. Thanks.

Manny

 

[Thayne]

If nobody on here has any concrete info, see if you can find a manual (On the net) that goes into detail on your or various scanners operational info.
A lot of times overclocking a microprocessor does not turn out for the best; and for all your trouble you could end up with something unreliable; but if you have the time why not research it? I would guess that most scanners don't have much of a microprocessor to keep the cost low, so may not like to go faster, and don't forget that the main thing is that it has to always have a "sample time" that IMHO would be the most important limiting factor as to speed---

 

[N1SQB]

If nobody on here has any concrete info, see if you can find a manual (On the net) that goes into detail on your or various scanners operational info.
A lot of times overclocking a microprocessor does not turn out for the best; and for all your trouble you could end up with something unreliable; but if you have the time why not research it? I would guess that most scanners don't have much of a microprocessor to keep the cost low, so may not like to go faster, and don't forget that the main thing is that it has to always have a "sample time" that IMHO would be the most important limiting factor as to speed---

I have already done the research. The scanner I am talking about is the Pro-2006 which is very well documented. The Bill Cheek mod book does say it is ok to be done as long as you keep it within reason. Stock crystal is 12 MHz. I am only talking about 16 or 18 MHZ to speed things up a little bit, nothing drastic. I have a spare front panel which will be my test dummy. So no harm will be done that cant be undone.....The book says microprocessor quartz crystal and that threw me for a loop.

Manny

 

[fineshot1]

I have already done the research. The scanner I am talking about is the Pro-2006 which is very well documented. The Bill Cheek mod book does say it is ok to be done as long as you keep it within reason. Stock crystal is 12 MHz. I am only talking about 16 or 18 MHZ to speed things up a little bit, nothing drastic. I have a spare front panel which will be my test dummy. So no harm will be done that cant be undone.....The book says microprocessor quartz crystal and that threw me for a loop.

Manny

If you have the service manual it is referred to in the service manual as CX501 and is listed as a "Ceramic Resonator". The description and manufactures part number are the same "CST12.0MT" and is listed on the schematic diagram as being 12Mhz. When changing its frequency being "within reason" may be a tough call as all of these separate circuit designs(within the 2006) must be in sync. You may need to experiment with different frequency resonators to find a sweet spot.

You can probably order them from Bomar, ICM or other crystal manufactures but I do not see any exact specs on the resonator in the service manual. There is usually a HCU spec number or something similar as I have seen in the past. Hopefully the xtal manufactures have this part specs on file so they can make one or more for you.

EDIT: The CPU (IC501 = GRE-0918) is listed as being a CMOS device. These are very sensitive to static induced damage so be sure to use
all the necessary anti-static precautions when working around and soldering near the CPU.

 

[N1SQB]

Thanks for the info. Yes, I do have the service manual. I have done this once before. The problem is, that was around 1992 when these were still around new. I dont have that radio anymore and I had just gotten sentenced to marriage, so I was not worried about saving or keeping any informatiion around. We were busy looking for a home, moving,strapping on the ball and chain for a good fit, ect....Man I wish I had kept that radio. I'm familiar with the static thing. I have done a few mods to those scanners that have the dimmer switch which also requires exposing and working around the underneath of the heat shield. Cant be too careful there... As I said, this is a test dummy 2006. My main 2006 is untouched, going strong next to my other scanners. That one I don't touch unless I am 110% sure of what I am doing......

Manny

 

[gewecke]

This may not help,but if the radio doesn't scan fast enough for you have you thought about simply entering duplicate frequencies of choice? It won't make it faster,but it will "see" those channels more often.
After all you do have 400 at least, to work with.
N9ZAS

 

[N1SQB]

This may not help,but if the radio doesn't scan fast enough for you have you thought about simply entering duplicate frequencies of choice? It won't make it faster,but it will "see" those channels more often.
After all you do have 400 at least, to work with.
N9ZAS

Geweke;
Thanks for the suggestion! This is more like a curiosity type project and not a MUST DO type of thing... I have always wanted to do this since I sold the one I originaly did it to in 1992. I was not smart enough to write things down back then. Now I could kick myself ....I may just try it anyway with the regular quartz crystal. Its only a spre practice scanner anyway...

Manny

 

[trimmerj]

It is a ceramic resonator. I bought a bunch from DigiKey years ago. I did notice that delay time was reduced and scanner was less likely to stop on an active frequency. Probably better off leaving it as is.

 

[gmclam]

Scan speed

I am in the process of modifying one of my scanners to make it scan faster. Now the mod calls for a
"quartz microprocessor crystal" of a higher value.

It sounds like this MOD is changing the speed of the CPU in your scanner in order to change the scan rate. BAD IDEA for quite a large number of reasons.

I will assume that you want to make your scanner scan faster; as I can't imagine many folks going through too much to make it go slower. Generally speaking when circuits run faster, they will consume more power. Additionally they will generate more heat. But those are "minor" issues.

One consideration would be whether or not the CPU and supporting circuitry CAN run faster than it currently does. Oh sure it might do that when you first make this MOD, but what happens when batteries get weak or you are in a hold or colder environment than usual? Or when the components age (more)?

Next, just making the scanning faster does not make it work. It actually takes a measurable amount of time for the radio signal you are receiving to get from the antenna connection to a point detected by the CPU. Change channels/frequencies and there is another measurement.

Years ago I added CPUs to my PRO-10 and PRO-77 scanners and wrote custom firmware to do the scanning. I was quite surprised at how long I had to wait on a channel to detect a signal, even if the signal was present before I got there. For the hardware I was using (crystal controlled remember) it was around 125ms. I could have easily made the scan speed 100ms or 1/2 of what I coded, but the bottom line is it did not work. I needed every bit of that 125ms (8 channels per second) so I did not miss signals.

Bottom line here, if you want a "faster scanner", purchase one that is designed with the scan speed you need. Many of those MODs out there are good at selling books, but don't provide a lot of real value.