can use someone’s knowledge w/ President HR2510

[Crambone]

Display not showing anything other than modulation bars, no frequency or anything else.
Unit receives 400, 1000 & 2900 HZ test signal on AM
Showing 7watts dead key and modulation
All buttons and knobs on radio are working.
I did find a few bad electrolytic but haven’t checked all, the ones that failed were replaced.
I also tried another screen.

Any suggestions on were to start would be appreciated as I’m not very tech savvy so make it repairs for dummies!

 

[Lkaskel]

The one popular issue with them is the corrosive glue they used to hold parts in place. Look for some youtube vids on that issue and you will see what I am talking about. You can remove the glue on your own but take your time and be careful. I am wondering if you may have a bad trace or part due to the glue.

 

[nomadradio]

The display-driver chip IC501 has three electrolytic capacitors connected to it. They serve to generate the display's operating voltage. If one of them fails, the display may go blank.

They're marked C501, C502 and C503 on the schematic.

May be a long shot, but a logical place to start.

73

 

[Low_Boy]

I usually recap the cpu board. It is a pain. Double sided board. Usually cures the problem.

 

[sp5it]

Did you check if 5v is present on IC501 an IC502?
Mike

 

[Crambone]

Thank you everyone. I’ve decided to start with recapping the unit as the ones I have already checked were bad. I will also remove the corrosive glue (carefully).
I haven’t checked for 5v wet on IC501 and 502. I will check that prior to recapping.

Thank you everyone for your help I appreciate it. I will keep you posted of my findings. Now to look for a list of caps for this thing.

 

[Shadetree Mechanic]

A member here Klondike Mike sells cap kits. He probably has one for your radio.

 

[Klondike Mike]

... Now to look for a list of caps for this thing.

You can start looking here;

https://www.ebay.com/itm/143099219153

 

[Low_Boy]

Did you check if 5v is present on IC501 an IC502?
Mike

Also on the cpu board IC 3118V and IC 312 5V

 

[sp5it]

Now to look for a list of caps for this thing.

First diagnose problem, than you can butcher your radio.
Mike

 

[AudioShockwav]

Second what has been said here.
The two regulators that Low Boy mentioned are often held down with the bad glue ( Sony bond ) I have seen the display come back by just carefully lifting these two regulators up from the board and carefully removing the old glue.
The glue becomes conductive and shorts them.
All of these 1980's radios are now showing there age.
Next the three caps Nomad posted about.
I agree you should fix the display problem , then you can recap the whole radio like Mike said.



73
Jeff

 

[AudioShockwav]

What Low Boy said about the double sided board is important.
Some of the holes on the CPU board are through plated.
That means that the top and bottom traces are connected by that hole the component is mounted in.

73
Jeff

 

[Crambone]

You can start looking here;

https://www.ebay.com/itm/143099219153

Ordered it from you thank you

 

[Klondike Mike]

Ordered it from you thank you

I shipped off a 2510 kit today, that must have been your order. Thanks for the business and good luck with the repair.

 

[Chevboy0167]

I use GC Electronics Radio -TV Service Solvent to remove that stupid Sony Bond glue crap. It will soften it up then you can gently pick it away. It's about $40 shipped from eBay for a 16 fl oz. glass bottle and it should last a person a lifetime!

Just remember to put a small amount in a glass 2-3 oz container and place the component in it for a while. Use this solvent in a WELL ventilated area as it is like paint thinner.

The two regulators on the CPU board must be re-glued down with thermal epoxy or install small TO-220 thin heatsinks and glue down to CPU board to remove heat. This new glue can be found on eBay or Amazon in a small white tube called Thermal Glue, HY910. It will not conduct electricity and remain pliable for many yrs. I have even upgraded these regulators from stock 500ma to 1.5 amp Motorola to last longer.

Please use a grounded tip soldering iron, an anti-static work mat with a ground wristband strap to put on the underside of your wrist. This all can be had cheap these days and the CPU chips are very sensitive and are getting harder to find. Ask me how I know!

It's very tedious work and take no shortcuts. Devote a clean work area, take your time and show an old rig some love and she will run for 40 more yrs I hope. Remember, I'm pulling for ya... we're all in this together!