Hi Jim...
Do you want the schematic for the audio processor or the main board ?
I need the full number for the board ie 43-911916 or whatever you have.
My experience with the MT-3 that you need the manual for the exact board no.
or you will have difficulty in getting it to work properly. The biggest issue I usually
have is getting to pass the audio. I try and find the exact manual then set the default jumpers
and that usually works well.
Mike VE7SML

I am working on a circa 1995 MT-3 transmitter for an APRS digipeater.? the last 2 of the board number are 16.? I thought it was like the later boards that I could just jumper and bypass the 600 ohm transformers with jumpers 19,20 & 22,23.? however this board does not have those jumpers.? I search around a bit, and I cannot find the schematic for the older MT3 transmitter.

any suggestions?? FYI the audio processor is a V1.6

TNX Jim?

Hi Ramon,
I have worked with many AC-3 audio cards, I am quite sure that there are no jumpers that will switch the logic on the COS signal.
You can change whether DTMF control of the COS signal will turn off/on the COS signal with a valid DTMF string. This requires
that a DTMF card is installed.
Will be interesting to see if anyone else chimes in with a different answer.
Mike VE7SML

I have an mt3 with ac3 card and ts-64 decoder.
works great.

COS or actally RUS goes from high, no signal, to low on
receiving carrier and proper PL. This uses an RC210
arcom controller. I want to use a different controller
that requires 0 volts no signal, and hi on valid carrier
and PL.

I can use a 2N2222 to change the RUS logic, but was
wondering if there is a jumper in the AC3 to do this?

Thanks

--
Ramon Gandia AL7X
Nome, Alaska USA

--

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Hi Jim,
when you say "with RXA decode"? , are you referring to the CTCSS decoder board(s)
or are you referring to active COR?
Active decode from the CTCSS board shouldn't be causing PTT activation.
If you are referring to active COR, then check the jumpers on the master program board.
If RXA and TXA are the drop , then JU6A should be jumpered. ( CORA - PTTA enabled).
JU6B should be unjumpered , having JU6B jumpered will caused CORA to activate PTTB.
mike VE7SML

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Good morning, I am working on a repeater for a small group of hams.? I am hung up because I don't have the manual for the 48 pin AC-3 audio card.? I am having trouble with both TXA and TXB are getting keyed with RXA decode.? The shelf is configured with TXA/RXA as the repeater pair, and TXB/RXB is for the APRS Digi.? Al I have is the AC-3E 96 pin audio card info.

TNX Jim??

I sourced the internet and my file for the manual for the HP front end preselector.? I have the low current manual but not the high current one.? anyone have this ?? TNX Jim?

Hi Bobby,? ?msg sent via email today let me know if you don't receive it?
tks,? Reid? W6MTF

I came across some UHF Daniels modules in my stash and was thinking of using them for a 6M split site rptr.
I recalled this thread after I searched for a rack, remembering I gave away a Receive only rack last year.
Today I saw some backplanes on ebay but no rack frames for them.
And if any brave souls with more energy and experience than I have actually do a conversion form 40-50 MHz up to the 52MHz region I might get the nerve to attempt that.
Meanwhile l need a Daniels rack to be able to use and test my UHF 420Meg modules,? they certainly would look nice sitting next to a Daniels 6M recvr.
as a compact package.?
73,? Reid? W6MTF

I think it's highly unlikely these things are going to make the move without component changes.

Chris

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Found alot more low band racks, now have abt 10 racks+ now after selling some... A few buddys have some now as well i may get around-tuit as for documenting more abt it.