Hello,
One of my HR2510’s gave me a similar problem with the radio turning on, but no display on the screen. I suspected bad capacitors as I already had to change other caps in some of my 2510’s & it seems to be common with the age of these things.
The one that had this problem was the one I use in the mobile, I don’t use it very often & it mostly sits on the shelf, well when it sits for a long time, a couple weeks, or couple months it had a severe delayed turn on, meaning it would have to sit on with the blank display for several minutes or at times seemed like 10 minutes or more then it would finally “come on completely” & work fine. Once it finally came on I could shut it off & turn it back on throughout the day & it would be fine, just could not let it sit for a week plus. I had previously changed a couple caps off the regulators on the CPU board & thought it took care of the problem but it did not.
I finally recently took it apart & started checking voltage on the CPU board & found some odd reading or missing voltages when compared to my other fully working 2510. I was eventually lead to IC314 which had no output voltage on pin 5 which is suppose to be about 5 volts when the radio is on & functioning. I guess IC314 is a delay turn on IC & controls the voltage to the reset or stop pin of the CPU & with no 5 volts present on that pin it will not come on. IC314 has a timing capacitor connected to pin 4 that controls the turn on time of the output of the IC which is C392 according to the schematic at cbtricks (I’ll post a picture of the CPU board, & circled C392 so you can see where it is located). C392 is a 0.1uf 50 volt electrolytic capacitor. I pulled the capacitor & tested it out of circuit & it was WAY out of tolerance. I checked it with my multimeters capacitance check function (which is fairly accurate) & it showed it at over 1.3uf so it seemed to be leaky & I suppose the value could be worse at times & could of accounted for the extra long turn on time, I also checked it with my ohm meter & it looked like the resistance is a little more then it should be as well. I replaced the cap with a good 0.1uf 50 volt cap & it has been working fine since, I let it sit for a week or so then power it up & it came right on just like my other 2510. I’ll let it sit for a month or so & retest it, hopefully that took care of the problem. I plan on re-capping all my 2510’s when I get the chance, been wanting to for a couple years now.
I also have another 2510 that the CPU board seemed dead, again no voltage on the output pin 5 of IC314, but this time the capacitor tested ok, I replaced it anyhow but it was still dead, after more testing I found that IC314 is dead & won’t put out any voltage at all, I bypassed it & manually applied 5 volts to the output pin & the CPU came right on & seemed to function fine, so you may want to check around that area.
I’d suggest completely re-capping the radio as who knows how much life is left in the original caps.
Anyhow, here is the picture of what seemed to be the problem cap in my radio (hope I post the picture ok):
One of my HR2510’s gave me a similar problem with the radio turning on, but no display on the screen. I suspected bad capacitors as I already had to change other caps in some of my 2510’s & it seems to be common with the age of these things.
The one that had this problem was the one I use in the mobile, I don’t use it very often & it mostly sits on the shelf, well when it sits for a long time, a couple weeks, or couple months it had a severe delayed turn on, meaning it would have to sit on with the blank display for several minutes or at times seemed like 10 minutes or more then it would finally “come on completely” & work fine. Once it finally came on I could shut it off & turn it back on throughout the day & it would be fine, just could not let it sit for a week plus. I had previously changed a couple caps off the regulators on the CPU board & thought it took care of the problem but it did not.
I finally recently took it apart & started checking voltage on the CPU board & found some odd reading or missing voltages when compared to my other fully working 2510. I was eventually lead to IC314 which had no output voltage on pin 5 which is suppose to be about 5 volts when the radio is on & functioning. I guess IC314 is a delay turn on IC & controls the voltage to the reset or stop pin of the CPU & with no 5 volts present on that pin it will not come on. IC314 has a timing capacitor connected to pin 4 that controls the turn on time of the output of the IC which is C392 according to the schematic at cbtricks (I’ll post a picture of the CPU board, & circled C392 so you can see where it is located). C392 is a 0.1uf 50 volt electrolytic capacitor. I pulled the capacitor & tested it out of circuit & it was WAY out of tolerance. I checked it with my multimeters capacitance check function (which is fairly accurate) & it showed it at over 1.3uf so it seemed to be leaky & I suppose the value could be worse at times & could of accounted for the extra long turn on time, I also checked it with my ohm meter & it looked like the resistance is a little more then it should be as well. I replaced the cap with a good 0.1uf 50 volt cap & it has been working fine since, I let it sit for a week or so then power it up & it came right on just like my other 2510. I’ll let it sit for a month or so & retest it, hopefully that took care of the problem. I plan on re-capping all my 2510’s when I get the chance, been wanting to for a couple years now.
I also have another 2510 that the CPU board seemed dead, again no voltage on the output pin 5 of IC314, but this time the capacitor tested ok, I replaced it anyhow but it was still dead, after more testing I found that IC314 is dead & won’t put out any voltage at all, I bypassed it & manually applied 5 volts to the output pin & the CPU came right on & seemed to function fine, so you may want to check around that area.
I’d suggest completely re-capping the radio as who knows how much life is left in the original caps.
Anyhow, here is the picture of what seemed to be the problem cap in my radio (hope I post the picture ok):
