[R-390] Measuring Resistance Values

[Barry]

Hi Bob,

Actually I was checking both. It was the resistance values which were extremely high and I was trying to make sure it wasn’t because of the meter I was using and I suppose it wasn’t. 

When I get it reassembled, I can check voltages with something more appropriate. 

Thanks,
Barry

> On Sep 2, 2024, at 11:33 AM, Bob Camp <kb8tq at n1k.org> wrote:
> 
> Hi
> 
> Ok, I’m guessing we have a typo. 
> 
> We’re measuring voltage at the test points rather than resistances. Let’s see, I’ve probably only made about 10 typo’s in this message so far … :) :)
> 
> Some of the old VTVM’s had pretty crazy input impedances. It would a bit unusual to find one that was above 10 Meg *and* something you would use in a radio with hundreds of volts running around in it.
> 
> Something like a Simpson 260 would be a much lower input impedance device when set up for looking at test point voltages. Simple answer in this case, grab that Simpson and see what it reads.
> 
> Bob
> 
>> On Sep 2, 2024, at 10:31 AM, Barry <n4buq at knology.net> wrote:
>> 
>> Did Collins specify what input impedance a meter should be to properly read the resistance values in the manuals?  I did see where a TS-352 was mentioned but that's selectable between 20,000 ohms/volt and 1,000 ohms/volt.
>> 
>> I started checking the RF Deck in my R-390 and, starting with V201, I noted a few values that are significantly high.  I was using a modern DMM with 10M input impedance so not sure if that could be the problem but I doubt it would account for that much difference but who knows.
>> 
>> The voltages were off a bit as well but not nearly as much as the resistance values.  I suspect the radio will still work with wacky voltages but the R values really have me thinking I have work to do.
>> 
>> Thanks,
>> Barry - N4BUQ
>> ______________________________________________________________
>> R-390 mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/r-390
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:R-390 at mailman.qth.net
>> 
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>