Re: Syncal 30 TRA-931 frequency dial lights?
Phew, my memory is not as bad as I thought.?
The external speaker box I made had a power connector ( Deans style T connector) for charging the battery pack via the front micrphone connector
Fig 3 of the manual shows power on pin B(+ve) and pin D(-ve)
Don't laugh at the next comment.?
I couldn't find an inexpensive male microphone connector so I made mine with male pins from a different connector, and hot melt glue ( stabilize the pins).?
Alignment is is not guaranteed so I have an external guide .
P
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Re: Syncal 30 TRA-931 frequency dial lights?
May be I will take the power from the microphone connector if present or mod' the mic connector.
I think one had power for the external speaker box that I made.
BTW the aluminum panel that had 7 glass ampules of tritium + phosphor, the one for the fine tune was smashed
the remaining six or all equally very? dim.
P
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Re: Syncal 30 TRA-931 frequency dial lights?
Peter, My dessicant had been removed long before I got mine. I snaked the wires through the dessicant hole and put a duct tape cover on it. Good work! Bill KE3BK
Partially mod'd
In order to get contrast I had to drop the LED brightness for the photo, and also my hand shake made it blurry.?
Don't really want to drill a hole to? pass the power leads through.
P
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Re: Syncal 30 TRA-931 frequency dial lights?
Partially mod'd
In order to get contrast I had to drop the LED brightness for the photo, and also my hand shake made it blurry.?
Don't really want to drill a hole to? pass the power leads through.
P
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Re: Syncal 30 TRA-931 frequency dial lights?
good luck! I bet it will turn out great!?
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Re: Syncal 30 TRA-931 frequency dial lights?
Found some 12 and 5V LED strips in my junk pile. Both use 150 ohm resistors.
The 12V strip was confusing. Each LED was a module with three individual white leds.
Three parallel strings of three each with a 150 ohm ballast resistor.
The 5V led strip, had 1 led per module and a 150 ohmresistor. So I wired 6 in series,?
but at 24V it was way too bright so I put in a 3.3k series resistor. Only needs 2mA.
?So next is the mechanical disassembly.
P
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Dave:
My 931 has a mute line that is used when an external speaker is used.
When I first tried an external speaker /amp I got RFI. Once that was sorted out, when transmitting , garbage comes out of the audio line, unless the mute line is used to mute the?
external amplifier when transmitting
P
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Re: Syncal 30 TRA-931 frequency dial lights?
smart mod.
tritium half life ~12 yr
I plan to do the same mod!
p
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Re: Syncal 30 TRA-931 frequency dial lights?
Tritium fades in about 10 years if I am not mistaken?
I installed leds on mine
https://youtu.be/1_2Vt_BhTYg?si=PY5vkscabDIHQaQR
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Syncal 30 TRA-931 frequency dial lights?
Hi:
if I let my eyes adjust to a pitch black room, I can see the "beta" lights glow just enough to read the frequency dials.
However in a recent post, another unit's back light appears very bright in room light.
Did some of the radios use lamps or LEDs for lighting ? or the beta emitter lights are way brighter when new?
my unit's serial number is 004366
The serial number indicate that this is a really old unit ?
I think mine came from Iraq
P
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Ststic crashes that aren't changed by the volume control? First clean
the volume control, then look for bad coupling capacitors in the audio
amp circuits after the volume pot.
--scott
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Hi Dave,
The common problem on those radios is the antenna relay.
I had to change the relay many times to find a good one.
Dirty or not closing well contacts, probably.
Try a new relay.
73 de Alex, HB9DTA
Update here on the Hamvention TRA-931X.
I am a happy camper at the moment.
This rig does well on TX.
I have used it on 75m phone with a external antenna with good results.
I have made several CW contacts with it also using an external antenna.
Can you believe SP3CW from Delaware on 15M after dark!
The receive audio seems to be the only source of trouble.
I have made a breakout box and have a amplified speaker attached.
There are static noises similar to lightning crashes most of the time
that are constant? even when varying the volume control on the rig.
I have not tried this on my other TRA-931 yet but last used with that
rig there was no audio trouble.
The audio output of the 931X seems to be very low by itself.
Using a H-250/U handset I have the volume all the way up and I barely
have noise or hear voices.
Also the receive audio is still there when transmitting SSB or CW, it
does not mute when transmitting.
Any ideas.
Dave KC3AM
On 5/21/2024 6:42 PM, Dave via wrote:
> Hello everyone,
>
> I found a TRA-931X at Hamvention last week, s/n 14643.
> No screws to hold it in the case and no battery pack.
> Opening it up it looks great inside at first glance with no signs of
> trouble.
>
> I see that it has a circuit board above the T/R relay which my 931
> does not.
> Also on the front it has two more BNC connectors.
>
> I do not have the manual for the 931X version yet to let me know what
> the differences are.
>
> Can anyone give me an idea of what I have here?
>
> Cosmetically it is a bit rough and dirty looking with some damage.
>
> Upon power up I have 18 watts on 21.260 in the tune position. I have
> not tried any other band.
> The frequency backlights all work with a Green color.
> The audio noise is there but a bit low and there are louder crackle
> noises that do not change with changing the volume control.
>
> When I input a signal from a service monitor on 21.260 AM, CW or SSB I
> do not hear anything.
>
> Any thoughts ???
>
> Thanks much,
>
> Dave KC3AM
>
>
>
>
>
>
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Update here on the Hamvention TRA-931X.
I am a happy camper at the moment.
This rig does well on TX.
I have used it on 75m phone with a external antenna with good results.
I have made several CW contacts with it also using an external antenna.
Can you believe SP3CW from Delaware on 15M after dark!
The receive audio seems to be the only source of trouble.
I have made a breakout box and have a amplified speaker attached.
There are static noises similar to lightning crashes most of the time that are constant? even when varying the volume control on the rig.
I have not tried this on my other TRA-931 yet but last used with that rig there was no audio trouble.
The audio output of the 931X seems to be very low by itself.
Using a H-250/U handset I have the volume all the way up and I barely have noise or hear voices.
Also the receive audio is still there when transmitting SSB or CW, it does not mute when transmitting.
Any ideas.
Dave KC3AM
toggle quoted message
Show quoted text
On 5/21/2024 6:42 PM, Dave via groups.io wrote: Hello everyone,
I found a TRA-931X at Hamvention last week, s/n 14643.
No screws to hold it in the case and no battery pack.
Opening it up it looks great inside at first glance with no signs of trouble.
I see that it has a circuit board above the T/R relay which my 931 does not.
Also on the front it has two more BNC connectors.
I do not have the manual for the 931X version yet to let me know what the differences are.
Can anyone give me an idea of what I have here?
Cosmetically it is a bit rough and dirty looking with some damage.
Upon power up I have 18 watts on 21.260 in the tune position. I have not tried any other band.
The frequency backlights all work with a Green color.
The audio noise is there but a bit low and there are louder crackle noises that do not change with changing the volume control.
When I input a signal from a service monitor on 21.260 AM, CW or SSB I do not hear anything.
Any thoughts ???
Thanks much,
Dave KC3AM
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Re: Dallas Lankford AGC Hang MOD for RA 6790
This?delays the RF relay which mutes the RF and Audio circuits.
?
Gary
---------- Original Message ---------- From: "Graham" <g0nbd@...> To: [email protected]Subject: Re: [RacalRadio] Dallas Lankford AGC Hang MOD for RA 6790 Date: Sat, 25 May 2024 08:19:19 -0700 On Fri, May 24, 2024 at 10:22 PM, gewingerd@... wrote:
RF and audio circuits
Gary -?
This affects? the? Audio ?
This adds? TX mute to the? 6790 ?? same as the? 1972 ??
or simply mutes audio - ie- is agc? addressed to
prevent it desensing due to local? tx? ?
Tnx- Graham?
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Re: Dallas Lankford AGC Hang MOD for RA 6790
On Fri, May 24, 2024 at 10:22 PM, gewingerd@... wrote:
RF and audio circuits
Gary -? This affects? the? Audio ? This adds? TX mute to the? 6790 ?? same as the? 1972 ?? or simply mutes audio - ie- is agc? addressed to prevent it desensing due to local? tx? ? Tnx- Graham?
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Re: Dallas Lankford AGC Hang MOD for RA 6790
The hang delay circuit works with the A1A1 to delay the RF and audio circuits after you release the TX key and delay the receiver by 1 to 15 seconds because the older transmitters have a delay in them blowing out the A2 FETs in the mixer box.
Gary
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Show quoted text
---------- Original Message ---------- From: "Dan Rae via groups.io" <danrae@...> To: [email protected]Subject: Re: [RacalRadio] Dallas Lankford AGC Hang MOD for RA 6790 Date: Fri, 24 May 2024 07:08:18 -0700 Bruno, Dallas's AGC Hang mod involved changing several resistors on the A4 board to alter the Hang times and adding a series R and diode combination to shorten the attack time.? It is really a matter of personal preferences.? I don't have an electronic copy of it. I've no idea what Gary's circuit does but it is only applicable to a GM fitted with the A1 RF amp module (or a 1792 of course). 73 - Dan - ac6ao
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Re: Dallas Lankford AGC Hang MOD for RA 6790
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Cesar