[MRCA] T-195B and volts

[Ray Fantini]

AC synchronous choppers, the hart of auto tune discriminators are very frequency sensitive. What may be happening is not an issue of voltage but of frequency. The solid state replacement inverters in the later models may produce a more tolerant 400 cycle source for the choppers then the old dynamotors and perhaps the old dynamotor versions tended to change frequency beyond the tolerance range of the choppers due to poor regulation or sag when keying the transmitter. Remember that frequency of the output of the dynamotor is directly proportional to the speed of the motor itself.
Radios like the ARC-38 and the 180L automatic antenna tuners use the choppers and they were tolerant of working only with in about 20 cycles above or below 400 cycles, I am assuming the 400 cycle source in the T-195 is one of the dynamotors and not a solid state inverter.

Ray F

-----Original Message-----
From: mrca-bounces at mailman.qth.net [mailto:mrca-bounces at mailman.qth.net] On Behalf Of B. Smith
Sent: Monday, September 28, 2015 3:33 PM
To: grasshopper; mrca at mailman.qth.net
Subject: Re: [MRCA] T-195B and volts

First things first, I would look at all power supplies especially the
400 cycle system, check servo power supply input and output voltage and look at the 400 cycle wave form , maybe the 400 cycle wave form is getting chopped up at lower voltages. But don't expect a nice sine wave but look for it to be consistent in frequency etc.
Z

On 9/28/2015 2:28 PM, grasshopper wrote:
> Would expect that as well..  I only have one sample.  I don't recall 
> if Ted mentioned his 195 was sensitive or not?  Do you recall what 
> voltage that rocket looking battery charger he uses as a PS maintains?
>
> Steve, kd3ht
>
> -----Original Message-----
> From: Dennis DuVall [mailto:duvallddennis at gmail.com]
> Sent: Monday, September 28, 2015 2:15 PM
> To: Grasshopper
> Cc: B. Smith; mrca at mailman.qth.net
> Subject: Re: [MRCA] T-195B and volts
>
> OK, your "B" would have the the solid-state replacemants for BOTH 
> dynamotors.  My -195s both have the mechanical LV/400cps units which 
> makes a difference at 22 volts maybe?  Still, a vehicular system like 
> this should be supply voltage tolerant over a wide range as pointed out by someone else..
>
> Dennis D.  W7QHO
> Glendale, CA
>
> *************
>
>> On Sep 28, 2015, at 7:48 AM, Grasshopper <grasshopper at epix.net> wrote:
>>
>> on my t-195b, i have found the with less than 28v, the low 
>> voltage/400 hz
> system will not engage.
>> Steve, kd3ht
>>
>> Sent from my iPhone
>>
>

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