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Messages - Robb

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Ham Radio Circuits and Repair / Re: President HR 2510 CPU/PLL issues
« on: March 08, 2018, 05:30:48 PM »
:hearing crickets?:

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Ham Radio Circuits and Repair / Re: President HR 2510 CPU/PLL issues
« on: March 06, 2018, 02:20:02 PM »
I understand thru another source that these CPU boards have their own issues.  Is there a link to any page that has documentation?  Couldn't find anything on the net that was worthwhile or complete.

Thanks!

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Ham Radio Circuits and Repair / Re: President HR 2510 CPU/PLL issues
« on: February 22, 2018, 04:07:45 PM »
I tested the three SMD varactor diodes (D305, 306, & 307) in the voltage adjustment circuit and they all tested OK.  Here is a strage factor: I can hear a change in the static volume level in the speaker when adjusting L317; it sounds like it is working.  But the test point shows no change in voltage at all; still reads 7.15v.  Very odd; wrong ground location for the meter?  Hmmm... 

So at the other side of this equation would be the NJM3404AS or the PLL0305A at fault.  Doubt that the S042P has anything to do with what looks like a short condition in one of these other device (yes; a guess), since it is a mixer chip at the receiving end of this chain.

Going to have to test the NJM and the PLL at their pins and see if anything is amiss.  Gonna have to go with the datasheets, since the schemo doesn't show voltages/signals values.

Thoughts?

http://www.cbtricks.com/radios/uniden/hr_2510/graphics/uniden_hr2510_cpu_sch.pdf

4
Ham Radio Circuits and Repair / Re: President HR 2510 CPU/PLL issues
« on: February 20, 2018, 12:09:23 AM »
Thank you Radio Tech for your reply.  Thing is, I replaced all of the caps in the radio including the CPU board.  Even tested all of those caps and only a few were marginal and a few shorted outright on the main board (one in the final bias circuit & two audio caps). Removed the glue too.

Just cannot understand why the voltage and freq adjustments on the CPU board are non-responsive?   The volt regs all tested OK as well.  Kinda stuck w/o a clue.  Have any insights where to look next?

Thanks!

5
Ham Radio Circuits and Repair / Re: President HR 2510 CPU/PLL issues
« on: February 17, 2018, 07:47:55 PM »
Addendum:  Both voltage regs on the CPU/PLL board tested OK.  Voltage reg for the main board also checked OK.

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Ham Radio Circuits and Repair / President HR 2510 CPU/PLL issues
« on: February 14, 2018, 08:46:42 PM »
Howdy, Radio tech and friends!
My first post here:

Have a 2510 that won't play nice.  Radio is TXing on 26.965mhz only - regardless of the display setting.  Using the Service Manual from CB Tricks BTW.  The VCO voltage setting won't change/adjust and is stuck on 7.15v @ TP 303 regardless of the freq setting; supposed to be 6.5v @ 29.699mhz/AM.  TP 306 is supposed to read 6.200mhz @ 28mhz,l but reads ~4.9mhz and won't adjust either.  Seems that none of the adjustments are working. 

Also, where is the ground point for testing on the CPU board? Think this may be my issue testing it and the settings issues.

I've worked on a lot of Galaxy, Cobra, and other CB radios; but never on a Ham 2510.  So I am a newbee to working on this radio.  Gonna test the voltage regs next.  Replaced all of the caps already.

Anything you can toss my way to help get this one in A1 working condition is appreciated.
Thanks!

BTW - the Service Manual does NOT cover all of the adjustment points; it really is lacking in that regard.  But that is the best I can find it seems.  SAMS Photofacts doesn't have a manual for it either? <shrugs>

http://www.cbtricks.com/radios/uniden/hr_2510/graphics/uniden_hr2510_sm_pg01_pg28.pdf

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