Pres HR2510 - What a Mess!

[Chevboy0167]

RIP.... sniff-sniff. Just checked a 477 out of another parts chassis...... he's.... he's dead Jim!

 

[Robb]

I have eight (maybe more) 2510's here in various states of customer didn't want to pay to have fixed.
Two are obvious , a crater in the middle of the 477
One was a modified clarifier, output of a regulator in the mezzanine to the top of the RIT and the bottom directly to ground.
Two smoked the audio chip, easy fix, replace the audio chip only to have them come back with a smoked audio chip some time later. Quoted a recap and here they sit.
One has the 477 replaced with a 455 stud mount. it was installed with base and collector reversed.
One has a dead chip, clock, regulator, who knows?
One was lighting struck, or, as hearsay goes it got tazered because the owner was a complete ass. Aside from the possible active device damage I found most of the receiver transformers open.

I have less than no interest in fixing them. I keep my several running but as they fail it's a case of diminishing returns. Do I really want to clear my bench (or dig it out of boxes even) just to spend hours with a 25 year old radio's voltage charts ? For what ? A 10, 11, 12m 30 watt multimode radio ? Keep in mind I have "several" general coverage radios with and without VHF/UHF so my opinion may differ from some.

I understand all that. SO, a solution occurred. Why not put them all in a box and sell them here on the forum? Surely there are a few of us that like to restore old radios - provided that your price is amenable and would be glad to relieve you of them.

 

[kopcicle]

Rob ,
As the tickets expire I'll consider it . One or two could be brought back with a chipswitch but as rare as those are ...
My personal parts radios are really just that (brings the total to ten) a car fire and a lightning strike.
The eight or nine here that the customer won't pay to fix are still in that " moment I off the radio somewhere the dolt will come looking for it" category.
I quit this as a business nearly 15 years ago but continued by word of mouth for another 10. It was hard to get rid of good and bad customers.In the end I got stuck with a bunch of stock and forgotten repairs. The worst case was some idiot that saw his radio for sale on craigs list and sent the Sheriff out to arrest me . I'd had the radio for 5 years.
Now I'm inclined to wait for an obituary before I move a radio that's been left. Someone here has already expressed interest in several and then the rest can go to blazes or the general membership. I'm just waiting for a few more death certificates ...

 

[Robb]

Say Robb... I have an original Blue dot MRF477 here that is a pull from a dead rig that shows hfe of 27 if you're interested?

Thanks.
But I ordered the upgrade MRF 497 from RF Parts already.

 

[Chevboy0167]

Good deal. I would offer ya one of my new old stock units but I have 2 2510s and a 2600 that I am saving them for just in case..... I have always wanted to try the "big pill" mod to one of these sometime... hmmmm.

 

[Onelasttime]

I don't normally get to work on these fine, old radios. But one came to me just the other day from a local trucker op that brings me his radios from time to time.

The amount of glue that holds the toroids in the back of the radio is daunting to remove. However, I have found that using the soldering iron will soften it up really fast and w/o damaging the board or the parts themselves. Makes removal from the board much easier. Problem is: what do I use to remove the glue from the toroid after it is out? Another problem: what kind of glue can I use to refasten it to the board that won't become conductive? Epoxy? Certainly not hot glue?!? I know; old clewing gum obtained from the bottom of a restaurant table?!?
lol . . .

Also had a problem with the heat sink getting too hot And something I have NEVER seen before: the speaker was getting so hot you couldn't keep your hand on it - and still worked!.

Turned out the MRF-477 had perished. Could it be because the person that installed it left out the mica insulator?!?

No doubt that it will need to get re capped. But there are nearly ~70 electrolytics on board. Figuring that replacing 15 caps/hour/average would mean close to/exceeding four and a half hours labor. Not to mention the fact that the cap kit will be nearly twice the price. Doesn't add up to a cheap bill. Gonna have to break the news to the customer. Guesstimate the bill will be $40 for the caps, $90 for cap replacement/labor, another $45 for a MRF-497MP (replaces the MRF-477 and can be purchased from 'RF Parts'). Then alignment will be another $50. That's 225 buckereenies w/o anything else it might yet need. If I charge for glue removal (I should); that will be another $30.

Nice old radio; but not a cheap date by any means!

As old as that beauty is you normally have to rewind the ferrite with fresh wire. If you get it back together and have issues with it those are likely the cause. I have known some guys to coat them with fingernail polish to get around rewinding them but that is hit and miss at best. That is a known problem. That and the glue on the CPU board under the voltage regulators becomes conductive and also causes problems freq. I seem to remember a delayed keying release fix as well that often needs to be done on those older radios. I think Rogerbirds site makes mention of this. I think it is just the addition of a cap to fix that.

The light bulb melts the little plastic shield around the LCD display so a lot of guys replace it with a white LED.

I have some photos some place of all the caps my President took. It was a crazy insane amount more than those Ebay kits contain. Also few if any of the electrolytic in my President Lincoln match the service manual used for the 2510 and 2600 all of mine had higher voltages and higher values, on the other hand, the none electrolytic caps matched the service manual exactly.

Their are 2 lytics and a ceramic in the audio line that you can change the value of to change the audio that passes. I went smaller on my lytics to pass more highs but the ceramic I went with a Wima film cap. Most guys get too agressive and go from the stock .22uf caps to 2uf which is just too much bass it ruins SSB. I went from .22 on those to .12 and used audio grade caps. THe cermic I put a 1uf Wima but some people go as high as 2uf but again all that bass while great on am it destroys the radio's SSB. I then run an eq, compressor and noise gate into this right through the mic jack. I can make it sound shrill for pile u busting or broadcast like for rag chewing.

 

[kopcicle]

...all mode operational and 500 milliwatt. :-/ As is it would make a decent QRP or driver for a high gain MosFet input. The output is as clean as the desigh sheet intended.
Now to figure out if it's 2166, 477, or further up in the 1973 or the 2086. Could even be some passive component. As usual I look in the back and both bias potentiometers are maxed...

...output varies according to bias setting for both driver and final but still no more than 500Mw . Also looks like someone disturbed all the potted toroids and several of the disc ceramics.

I don't seem to have the sensitivity to see beyond the DC component off the buffer and pre-driver atm. Need to futz with the probes and a possible low level broadband amp.

Before anyone goes off on shotgun repair and "just replace the driver and final" the 2166 is getting as rare as the 477/497 and the 2312/1307/1969. The failure mode is well understood be it a clueless butter knife monkey or reverse polarity (the driver and final are always connected to B+) . This exercise is because I need near assembly line proficiency. I may have mentioned that I have (had) 8 of these in house. I now have 12. I swear they multiply when I'm not looking. At least 3 of the 12 will be parts radios for the others and again, what is left is already spoken for. At least one hulk will go to a member here for cosmetic reasons and one stays here for the same reason. I hope to have small parts available and will post when that happens. In the mean time I'll keep this updated with what little progress and humor I have to offer.

 

[Handy Andy]

Hey!

Check the '497 with the datasheet.

The MRF477 has had problems with the Emitter being in the middle - meaning the die inside is different - and since one part of the Emitter is the Tab - the leg from the main PCB is not bonded to the tab, it's bonded to emitter which is connected to tab - a "fusible link" in some instances - at least ones I've had fail pop the emitter middle leg completely open so it wasn't even ohmic to the tab at all..

So the fix was for Uniden to go back to Ceramic heat sink units to keep the bond and loop issues down.

I hope your kit comes with that.

If possible please be aware of the history behind what is written above, and what the results brought us to now...

Regards!
:+> Andy <+:

 

[Low_Boy]

If someone has rewound the toroids and used uncoated wire or has wound them wrong that can be a problem. A bad ceramic disc cap. can also be the problem. You may want to pull the final and driver and put them on a tester. All are problems I have had with these HR2510's and some of the problems I have found even the glue on the 2 big totoids can cause this proble.

Like you Kopicle my collection of parts, Working and Lincolns has grown to an embarrassing +25 not to mention a HTX100.

 

[Handy Andy]

As one of the many signs; the user left the thing powered up all the time, it went into self oscillation until it did a meltdown and the owner came back to the vehicle only to find it with a dead battery and the wet hot electric smell in the cab and when we see scorched toroid's, they are a dead giveaway

 

[kopcicle]

https://www.worldwidedx.com/threads/2510-again.229145/#post-624542

Over here ^^^^