HR2510 cuts out

[JohnnyJJ]

I have an HR2510 that suddenly loses it's recieve and transmit. All lights stay on - the speaker has a little bit of soft static but won't recieve anything, the transmit isn't keying. If I disconnect it for a period, it will work good for a little bit then it will lose it again. I visibly checked for loose components
and/or a cracked board. I would really like to use this radio for a mobile.
I know most of it is still workable and whatever the problem is must be minor, hopefully someone knows about this problem ?

[Rick]

Check voltage regulator IC6 depending of year of you radio it maybe IC107, this is a 8 volt regulator pin 1 should be about 13 to 13.8 vdc pin 2 is ground and pin 3 should be 8 vdc. Connect a vom to pin 3 and monitor the voltage when the fault occur, if the voltage drops below 8 volts change the regulator. Hope this helps. Lets us know how you get on.

Rick.

[JohnnyJJ]

Thank you for the fast reply Rick.
I've been trying to find IC107, those numbers sound closer to what
I've been seeing. This board say's PB 111AC 1986.
What you described has three legs, and yet you said check pin 8
so I've been looking for an IC chip.
I do have 3 leg transistor that's attached to the side
that I can't find any number on the board for. I noticed
it feels warm also. I see the 2 power transistors attached to the back fins
also have no numbers on the board.

[Rick]

Sorry my error should be Pin 3, this is transistor you have found bolted to the side of the radio, this is a volt regulator and not a transistor.

Rick.

[JohnnyJJ]

I went ahead a got a replacement for the voltage regulator.
The orig was HA 17808
the Electronics Supply I got them (2) from
said their replacement part was NTE964.
I put it in, and it worked for a few minutes then went out
like before, only slightly different. Now when I try to key it,
I can see it try to transmit for a second. There is still no recieve
although there was when I first turned it on. They were only
3$ so I bought 2 and some heat sink compound.

[Rick]

That why I ask you to monitor the voltage when the fault occur. How amps is you power supply?

Rick.

[JohnnyJJ]

I just went ahead and replaced the Volt. Reg. because it really sounded
like that's what it was, and it was relatively inexpensive.. Checking the meter now, it say's mostly close to what you
said it should be, 13 and the other is right at 7. This little Micronta meter
is hard to determine exactly. I am using an 8 amp power supply.

[Rick]

Have you tried a different power supply or car battery? If the fault is not with the power supply then will need to monitor the 8 volt line at pin 3 of the voltage regulator when the fault happen, It should be at 8 volts and not 7 volts check with a second meter as you meter maybe giving the a wrong reading.

The fault could be one of the capacitors C149, C152 or C154 see diagram.

Rick.