125 watt VHF Quantar randomly drops TX

[KenHorse]

Running with an external controller, interfaced via the Telco connector with Wireline card. It randomly drop TX even though external PTT is asserted by external controller. When PTT from controller drops, TX once again works.

I've been monitoring the repeater remotely (via CSS) and nothing looks out of the ordinary. SWR, forward power, voltages, etc. look good (well, except no RF out during these times)

[crazyboy]

TOT?

[KenHorse]

I don't think so as it is disabled. And as I said, it happens totally at random, not based on any timer period

[N4DES]

Having the TOT to be controlled by the external controller is fine, but what I would try is to keep the TOT in the Quantar SCM and make for a time period that exceeds the external controller and see what happens. It just might not like being set to zero and is picking some random time period to time out.

[KenHorse]

Do you know what is the maximum value of the TOT or where can I find out? The HELP is not exactly chock full of info......

Edit: Nevermind. I see a mouseover in the CSS field says max is 2550 seconds.

[Astro Spectra]

When Quantars do random things it’s time to check the EEPROM in the SCM. Check if it’s the problem Xicor part or the good Atmel version.

[Jim202]

By any chance is the PA shutting down from high heat?

[KenHorse]

I don't think it's heat because the XMTR dies for the duration of hang time from the external controller. Once that happens, the TX is happy once more. Some times for hours