President Madison (MB8719) no AMC adjustment???

[loosecannon]

hi all,

i have a president madison here that i am about to restore.

it is the rare bird madison that has the analog clock and the MB8719 PLL chassis.

i opened up the SAMS manual for it to look at the alignment procedure, and couldnt find the AMC control adjustment.

in the grant/148gtl, its VR7.

in the 2000GTL its VR12.

in this chassis VR7 is the modulation meter adjustment, and VR12 is for the antenna warning indicator.

so, at the factory, did they just make sure the modulation was safely below 100% with the stock 10K value of R131?

or did they de-tune the transmitter coils?

anyway, i would like to have an adjustable AMC control, so i was thinking of replacing R131 with a 10K variable resistor.

does anyone have any insight on this?
is this the part to make adjustable?

any old tricks of the trade to get this thing up to 100% modulation?

anyone else find it strange that they didnt include a variable adjustment on a high end SSB base station from back in the boom days?

all comments welcome,
LC

 

[BOOTY MONSTER]

Madison Review

"Inside the radio you can adjust the SSB ALC (VR11) and you can adjust the AM deadkey (VR10) quite easily. This radio does not have a modulation potentiometer and so it's quite common to see people clipping the modulation limiters in the Madison radios."

FWIW

 

[loosecannon]

i asked a tech friend of mine and he said that R130 was the one to make variable.

looks like ive found my answer.

thanks for the reply booty.

later,
LC