Pro 2045 Service manual
- Thread starter W2SGX
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I own one. Bought it new in the early 90's. Never had a service manual. However, the main issue that develops with some of these radios is the failure of the capacitor that maintains the memory. It can be replaced easily and I did that a few years ago. When it fails the memory will be lost without power being connected. RS sold a chip that could be installed to give the radio CTCSS decode capability. Mine has one.
Basically it was an OK scanner for its time. Now, not so much. Analog wide band only and limited coverage. Steps are not always consistent with modern channel spacing. I would not waste time repairing it other than the capacitor. I still use mine once in a while. Mostly I just monitor the local fire channels. CTCSS decode is nice. Sensitivity is lower than modern radios.
Basically it was an OK scanner for its time. Now, not so much. Analog wide band only and limited coverage. Steps are not always consistent with modern channel spacing. I would not waste time repairing it other than the capacitor. I still use mine once in a while. Mostly I just monitor the local fire channels. CTCSS decode is nice. Sensitivity is lower than modern radios.
Yes I agree that it is not the greatest scanner going, but for what I use it for it works. Using a newer scanner that stores frequencies in search mode I transfer them to the 2045 and let them run for a few days. Then because the 2045 has a count feature that my newer BCT15X doesn't I can see if the frequencies are active enough to transfer to my main scanner another BCT12X. Yes seems like a lot of work but it is a system and it works for me. What I would really want is a schematic and block diagram for the 2045. That way I can do some experiments like creating a count circuit for the BCT15X.
Do you recall which capacitor you replaced? I have an extra 2045 (that loses memory) that I was willing to give the OP if his board or display was bad, but since that isn't the case I think I'll go ahead and replace the capacitor.
It looks sort of like a button cell, but it is a cap. Large and round. Not like anything else on the board. Don't recall the value, but its marked on the cap. Very easy to unsolder and replace. I got the replacement from Mouser I think. Can give you more info, but I would have to open up the radio and I don't have time to do that for a few days. PM me if you need more info.
YumaRoger
Newbie
Good site for scanner info: RadioPics Database - Main
Thanks for the info, and I wish the OP good luck.
ind224
Member
I want a 2045 service manual as well. One person said they had one in another thread but he is SK now.
sm6xqy
Newbie
I want PRO 2045 service manual to.
My problems is related to the squelsh Circuit.
when i have the receiver in scanning mode and
it stops scanning and You hear something, when
the signal is over the squelsh dont work, therfore
is it a constant noice in the speaker and it stops only
if i switch the scanner off and on.
(Sorry for bad English, but i am from Sweden)
73 de SM6XQY Tomas JO 57 TR
My problems is related to the squelsh Circuit.
when i have the receiver in scanning mode and
it stops scanning and You hear something, when
the signal is over the squelsh dont work, therfore
is it a constant noice in the speaker and it stops only
if i switch the scanner off and on.
(Sorry for bad English, but i am from Sweden)
73 de SM6XQY Tomas JO 57 TR
ind224
Member
European models are supposed to have 66-88mhz I wonder if there is a big difference? Is it just one freq in a specific mode locking up or all the time no matter what? Might be a birdie. I emailed Uniden about a manual but so far no reply.
Did Uniden make the Pro-2045 for Radio Shack? I always thought that model (like most of Radio Shacks scanners) was made by GRE.
I think Uniden's policy today is they will not sell service manuals. They did back in the day but that was long ago.
Radio Shack used to sell them for most of the models with their name on the scanner but I don't know if what little is left of Radio Shack would still be able to provide them.
There was also a point in time where Radio Shack would not provide manuals as people were using the info to circumvent the band switching section in order to receive the old AMPS cell phone band via images. The cell phone band was outlawed in an ECPA ruling twice. The second revision forced the manufacturers to cover the band switching components with an epoxy so that section could not be tampered with any longer.
sm6xqy
Newbie
@ Ind224.
I*ts all frequences and both AM and FM.
I*ts all frequences and both AM and FM.
Ubbe
Member
The SQ circuit are always monitoring the noise level in FM mode even if you are listening in AM.
First check that you do not have a discriminator tap that have gone bad. If the discriminators audio level are loaded too much it will not give enough noise level for the squelch circuit to detect and it will think that it is a noise free channel that doesn't need to be muted.
Then check that the SQ can be opened from the SQ dial and then closed again. I guess that this test will fail.
The SQ circuit are amplifying the noise and then use two diods and a capacitor to convert it to a DC voltage that are used to determine the level of noise in the signal and compare that to the level set by the SQ dial. There's a positive feedback resistor from the switching output to the input of the DC switch to create a hysteres, that the SQ will close on a higher level of noise once it has opened. If it's anything like a Pro-2042 the hysteres is huge, the difference between open and close of the SQ, and if the audio level from the discriminator are not high enough it will never close the SQ and mute.
/Ubbe
First check that you do not have a discriminator tap that have gone bad. If the discriminators audio level are loaded too much it will not give enough noise level for the squelch circuit to detect and it will think that it is a noise free channel that doesn't need to be muted.
Then check that the SQ can be opened from the SQ dial and then closed again. I guess that this test will fail.
The SQ circuit are amplifying the noise and then use two diods and a capacitor to convert it to a DC voltage that are used to determine the level of noise in the signal and compare that to the level set by the SQ dial. There's a positive feedback resistor from the switching output to the input of the DC switch to create a hysteres, that the SQ will close on a higher level of noise once it has opened. If it's anything like a Pro-2042 the hysteres is huge, the difference between open and close of the SQ, and if the audio level from the discriminator are not high enough it will never close the SQ and mute.
/Ubbe
sm6xqy
Newbie
I don´t have a discriminator tap on this scanner.
This problem starts for aboat 2 months ago.
Before the scanner works perfect.
I beleve some capacitor is the problem, but wich.
73 de SM6XQY Tomas JO 57 TR
This problem starts for aboat 2 months ago.
Before the scanner works perfect.
I beleve some capacitor is the problem, but wich.
73 de SM6XQY Tomas JO 57 TR
Ubbe
Member
If the two diods rectified audio are not filtered enough to a clean DC by the capacitor it might be the problem. Look for two diods close together and perhaps you can see where the cable from the SQ controller goes to the circuit board. It should be a smaller value capacitor like 0,1uF. Also check that the SQ controller haven't gone bad a need a spray of contact cleaner, or if the cable to it sits with a detachable connector then re-seat that connector.
/Ubbe
/Ubbe
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