I have 2 working Electra ( bearcats scanners ) and a third parts one
1 one is the bearcat 3 the other is the bearcat 4
the parts one is a 4
does anybody in the metro Cincinnati / northern KY area know of a good shop to have the radios look at
I listen to the radios on a daily basis but the hum in the speaker has got to go and they could use a cleaning and tweaking of there insides , I have newer radios,but my old school is showing
I'm not from your area so don't have an answer of someone local to repair but your mention of audio hum is clue.
The problem is likely just a dried out electrolytic filter cap in either the power supply stage or in the power supply section that powers the audio amp chip or transistor.
The power supply capacitor is really easy to replace and identify. It's the only large sized capacitor in the radio. One can even swap it without actually unsoldering it from the pcb. It has plenty of exposed lead on each end to cut the old out leaving exposed leads left behind, solder in a new cap of the same or higher values for both, capacitance and withstanding voltage (both will be printed on the old cap). You need to pay attention to which lead was the negative lead and solder in the new with the correct polarity. These radios were made in the mid 70's which puts them at over 50 years old. Electrolytic caps do dry out and no longer offer any filtering of ac components that would otherwise be riding on the trace they are soldered to.
Anyone comfortable with basic soldering should be able to swap this cap for you.
The other suspect cap would be smaller in physical size but still likely larger than other caps on the board. It would likely filter out ac components riding on the power traces around the audio amp chip or transistor(s).
They will also be of the electrolytic type cap. They can be identified by the fact they will be marked with the polarity of the wire leads coming out of them. Usually only the negative or (-) lead will be marked. This cap being smaller will usually be soldered in place standing up from the board.
Swapping it out can usually be done by snipping most of the cap away with side cutters and then soldering a new one to what is left of the leads still soldered to the board. Doing it this way may be easy but it is not very pretty. For this swap, you are really better off unsoldering the old cap from the solder side of the board, cleaning up any remaining solder still keeping the holes closed using a product often called "solder wick". Solder in the new but again, observe the polarity of the old before you remove it. Some boards are marked with a + or - symbol so you get the polarity correct but don't count on that. This cap can also be rated for a higher voltage but depending on where in the audio stage it is, the capacitance value should probably stay the same.
Sometimes you can see an old cap leaking or having visible corrosion on one of the wire leads or one end may be swollen looking. Both visual indicators that the cap is likely bad.
New caps are very inexpensive at under a dollar each depending on their size and can be ordered at places like Mouser. Mouser does not have a minimum order so you could order 50 cents worth of capacitors and they would ship them to you no problem. There is also a temperature rating on these type caps. Most from that era are rated at 85 degrees Celsius. That is just fine for this application but the next value up will be 105 degrees Celsius, either rating will work just fine. The caps are very common and will be available from many sources. eBay may be a better source as you will probably find free shipping but look for a seller in your country so you don't have to wait several weeks as it makes its way across the oceans! Also, pay attention to the case style of the old and new caps. They will normally be Radial or Axial. For a good looking replacement job, you want the same case style. There is a ton of room in these old radios though so the other case style can be used if you don't mind the look. It would be wise to hot glue the new capacitor to something if using a different case style so it is not just hanging by its own wire leads.
Swapping these caps will probably fix the hum you mention that can be heard through the speaker. These old models did have some slight hum in the audio even when brand new but it is usually a low enough level that it would not be noticed by most users. The audio stage filter cap will probably be the next size smaller cap smaller then the large one in the power supply stage. I forget if these old models can be powered with an external 12 volt DC power source but if they can, use a small 12 volt battery like UPS units use and power the radio with that. If the hum is now gone, the bad cap would be the largest one on the power supply stage as that stage is not used when running from an external DC source. If the hum is still present, it will most likely be a bad cap somewhere in the audio stage.
It took me way longer to type this than it would have to replace both caps so that should give you an idea of how easy it really is to swap them yourself or by someone halfway good with basic soldering skills.
Of course make sure all power is disconnected from the radio before you even open it up!
