[PCR-1000] no receive

[nt1g at comcast.net]

It would be interesting to compare a 'corrupted' eeprom's data with a
 good  one and see what bits had flipped.
 Perhaps a method of 'analytically' repairing a ROM image may be the easiest
 way to recover a unit...
--
Skip Flem, NT1G 
Hull, Massachusetts

-------------- Original message -------------- 

> About the PCR-1000 going deaf: 
> I still have an early PCR-1000 receiver, and have been following 
> this list more or less since the beginning. I think that the business of 
> third-party 
> software causing the problem was something put out by Icom as a way of 
> blaming 
> someone else. From following this list, I believe there have been quite as 
> many 
> EEPROM corruptions from people using Icom's own software, as from use of 
> any third party software - but Icom always denied that. 
> I still use the same PCR-1000 essentially daily. 
> I had no problems with the PCR-1000 for 6 years, and then one day the 
> EEPROM corruption struck, At the time I was using Win98, and had been 
> doing 
> so for some time. Fortunately I had an EEPROM backup, and after EEPROM 
> restoration 
> the PCR-1000 was back on the air, as good as new, in no time. It's been 
> running since then 
> for a couple of years. Before restoration I made a temporary backup of the 
> corrupted 
> EEPROM and examined it. It wasn't just a single byte here or there, but 
> essentially all 
> of the EEPROM bytes had been replaced by Hex#80. 
> I never found what had caused the corruption after 6 years of no problem. 
> It might 
> have been Windows interrogating the serial port. Another theory is that it 
> was my 
> power up sequence; I use relatively heavy duty 12 V power supply, and was 
> in the 
> habit of leaving the PCR-1000's own power switch turned on, and just 
> powering up 
> or down with the 12V PSU switch. I could imagine that, particularly after 
> I turn off the PSU 
> power, the nominal 12 V output decreases fairly slowly as capacitors 
> discharge. 
> You could imagine then that the slowly falling low voltage that's still 
> applied to the 
> PCR-1000 might cause the logic to get into some strange state which could 
> occasionally 
> erase the EEPROM. "Occasionally" could be once in every 2000 power cycles, 
> or about once per 6 years. 
> This is just a theory. Since that one EEPROM corruption, I've made a 
> point of only 
> turning on the PCR-1000 at its own switch after my PC has booted up, and 
> after 
> the 12 V PSU has been turned on. Similarly, before powering down, I first 
> turn off 
> the PCR-1000 at its switch, before shutting down the PC and powering down 
> the 
> 12 V PSU. Since doing that, there have been no further problems - at least 
> for 
> 2 years or so. But then, it took 6 years for the first and only problem to 
> appear, 
> so I guess I have to wait for a few more years to know if my better power 
> up and 
> power down sequence actually makes any difference. 
> 
> Good luck, 
> Darrel Emerson.