[GreenKeys] TU-170 with External Loop Supply
Daniel Jones
djones at k6yic.com
Mon Aug 16 08:44:36 EDT 2021
I will pop the cover off this evening and send a picture this evening but here is the basics.
1. I removed the fuse
2. I didn’t have a 1/4” Phono jack at the time and since I was permanently wiring it up to my 1203A patch panel I opened the case removed the jack unsoldered the wires and took the 2 wires and ran them directly to my 1203A. Red and Red White if I recall. If you don’t pull the fuse it will just blow which doesn’t matter anyways (R74 in earlier models will get hot and smoke and stink up the place, you need to clip this or unsolder it)
3. It handles everything just fine, a couple months back I ran a continuous feed from the auto start Channel for just under 1 hour. (Auto start to TU-170 to Reperf to TD to CV-2460 out to the world on 7087).
Daniel
Sent from my iPad
> On Aug 16, 2021, at 05:23, Paul Birkel <pbirkel at gmail.com> wrote:
>
>
> John: Common sense reigns on the C.T. connection, thank you.
> Now for my question about how your revision actually works with an external supply?
>
> I’m unclear on the connection points (internal and external) for the loop.
>
> From: greenkeys-bounces at mailman.qth.net [mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of John, W9DDD
> Sent: Monday, August 16, 2021 8:04 AM
> To: greenkeys at mailman.qth.net
> Subject: Re: [GreenKeys] TU-170 with External Loop Supply
>
> Well I remembered to look, but I couldn't remember where!
>
> In the meantime here's a snippet from a poor scan that appears on ElektroTanya.com. Actually in terms of showing the ground connection for the transformer's CTs, it's a better scan.
>
> <image001.png>
>
> You'll notice that R74 is present instead of the fuse, indicating this is from an earlier kit.
>
> ---
> ----
> The above comments or recommendations are SWAG. Use at your own risk.
> John, W9DDD
> On 8/16/2021 4:48 AM, John W9DDD wrote:
> I think the center tap to ground symbol connection has suffered the same fate as the connection between R60 and M. I will go fetch my hard copy later (if I remember) and see if it's any clearer. Some times a faint line will disappear in scan.
>
> John, W9DDD
>
>
> On Aug 16, 2021, at 3:37 AM, Paul Birkel <pbirkel at gmail.com> wrote:
>
> Daniel: [U] (TIP) now being disconnected (fuse removed) the wire-pair would be between [R] and what? [R] would be TIP? I’m not yet envisioning the revised circuit and how it would work with an external supply.
>
> (The published schematic for the TU-170 itself appears to be in error as the center-tap on the secondary of T1 and T2 isn’t indicated as being connected to chassis GND.)
>
> From: Daniel Jones [mailto:djones at k6yic.com]
> Sent: Sunday, August 15, 2021 10:56 AM
> To: John W9DDD
> Cc: Paul Birkel; Greenkeys
> Subject: Re: [GreenKeys] TTY loop jack boxes - SET, LPG, MISC
>
> I forgot to mention that I did remove C40 which couples the collector to chassis ground.
>
> I removed the loop jack on the back and run a pair of wires in its place without C40.
>
> (Side note if you have an older version only the TU-170 you might not have a loop fuse but a resistor in its place (R74), this would need to be removed to accomplish the same thing. I have both types).
>
> I have mine patched into my 1203a panel using a Navy PP-3494A/UG loop supply to make everything work.
>
> Also as a note I don’t believe that the meter will work or the current adjustments will be functional if you don’t have an external supply. It’s not necessary but diminishes the cool factor a bit in my opinion.
>
> Daniel
>
> Sent from my iPhone
>
>
>
> On Aug 15, 2021, at 07:26, John W9DDD <w9ddd at tapr.org> wrote:
>
>
> How are you handling the fact that the emitter of the switching transistor of the TU-170 is pretty much at circuit common.
>
> John, W9DDD
>
>
> On Aug 15, 2021, at 7:43 AM, Daniel Jones <djones at k6yic.com> wrote:
>
> Nick pretty much explained it but I will mention that I use a TU-170 connected to my 1203 but I utilize an external loop supply.
>
> I just pulled the loop fuse on the TU-170 and it now just utilizes the same external power supply that my other Terminal units require (CV-2460 adn CV-483). It has been operating fine forte last 5 or so months being on all weekend. The nice thing about the 1203 is the fact you can adjust the loop current for each channel.
>
>
> My 2 cents….
>
>
> Daniel Jones (K6YIC)
> DJones at k6yic.com
> http://K6YIC.com
> HH Phone #11973
>
>
>
>
> <logo-globe-600dpi.jpg>
>
>
>
> On Aug 15, 2021, at 3:21 AM, Paul Birkel <pbirkel at gmail.com> wrote:
>
> So … I’m still not the “sharpest crayon in the box” on this topic. Let me use the SB-1203/UG as my example (documented online at: https://www.navy-radio.com/rtty/sb1203.htm). It has six identical circuits (“channels”) – one example diagrammed at: https://www.navy-radio.com/rtty/patch/1203a-man-07.JPG
>
> Inside the unit there are several sets of terminal strips (see: https://www.navy-radio.com/rtty/patch/1203a-man-01.JPG) establishing pairs of permanent connections corresponding to the TB-* appearing at the bottom of the example schematic diagram.
>
> TB-101 would normally connect to some equipment (this is, I think, “(LINE LPG)” in the terminal strip diagram) that is _always_ in that particular channel (examples from that terminal strip diagram are “RADIO ADAPTERS, FREQUENCY SHIFT KEYERS, LINE MODULATORS”), and may optionally supply loop-current, correct?
>
> Alternatively TB-101 could be strapped closed under the assumption that there is a SET connected to TB-102 and there is a loop-supply established via TB-104 and the default strapping?
>
> The distinction between TB-101 and TB-102 seems to be whether the SET supplies loop-current or not, correct?
>
> TB-102 (SET jack) would connect to some equipment that is normally in that channel, but can be either:
>
> (1) removed from that channel by inserting some sort of “dummy” plug (has no internal wiring)? … or
>
> (2) removed from that channel and connected into some other channel using a patch cord
> that establishes a connection between two plugs where the second plug is then inserted into
> a LPG jack on another channel?
>
> TB-103 (MISC jack) would connect some equipment that is not in any channel, to some channel using a patch cord to a LPG jack?
>
> (The documentation for this unit is quite good; my comments above attempt to summarize my functional understanding of how it is intended to be employed as an exemplar of what I assume is a pretty standard approach to loop jack boxes.)
>
> Is “patch cord” the correct terminology? Is it just wired tip-to-tip and ring-to-ring (or shell-to-shell if two-wire)? Are they normally TRS (shell left unconnected?) or TS?
>
> Now, for a use-case, if my source were a self-powered loop from a Flesher TU-170 (which incorporates a loop supply and 0.125A fuse) it seems to me that I’d:
>
> 1. Strap the SB-1203/UG for REMOTE internally (rather than use the default strapping for a TB-104-connected loop supply).
> 2. Connect the TU-170 to TB-101.
> 3. Connect a (for example) M15 to TB-102 (SET jack).
> 4. Connect a (for example) M14 ROTR to TB-103 (MISC jack).
> 5. Connect a (for example) M14 TD to a different TB-103 (some other MISC jack)
> 6. Optionally add a loop-cable from MISC to an JPG jack to use the M14 ROTR to generate a paper tape of traffic between the TU-170 and M15.
> 7. Optionally add a loop-cable from other-MISC to an JPG jack to use the M14 TD to read a paper tape “into” traffic between the TU-170 and M15.
> 8. Optionally add a loop-cable from SET to an JPG jack in some _other_ channel to move the M15 to that other channel (which would need to have at least loop supply established).
>
> Would this be a reasonable approach? Would it be a _good_ approach if these were the four items to be co-employed in this use-case :->?
>
> Would it, in fact, be better to treat the M14 TD as a SET in a different (powered) loop in which case I could then either:
>
> A. cross-connect the M15 there, or
> B. cross-connect the M14 ROTR there, or
> C. cross-connect the M14 TD into the TU-170 loop?
>
> This seems like a more flexible approach assuming that there is available a separate loop supply for the second loop.
>
> Am I thinking about all of this “right”? Inquiring minds want to know!
>
> Thank you,
> paul
>
> (A long message, but I’ve not gleaned enough specificity from GK traffic archives. Hopefully by being pedantic here … we’ll avoid more “dull crayons” in the future :->)
>
> From: greenkeys-bounces at mailman.qth.net [mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of Nick England
> Sent: Sunday, August 08, 2021 3:33 PM
> To: Greenkeys
> Subject: [GreenKeys] Fwd: TTY loop jack boxes - eBay
>
> Argghh - I forgot to include the link to my page with schematic and explanation
> https://www.navy-radio.com/rtty-patch.htm
>
> In the schematic for this type of box, you will see that the LPG jacks are shorted when nothing is plugged in. When nothing is plugged into the SET jack, the associated equipment is in the loop. When you plug a cable into into the SET jack, the equipment is taken out of the loop onto the cable and the loop is shorted. This is so you can plug the equipment normally in Loop 1 into Loop 2 for example and vice-versa (jumper SET-1 to LPG-2 and jumper SET-2 to LPG-1).
>
> "NOTE: Anyone patching or unpatching circuits from a TTY panel must be sure to pull the plug from the looping jack (LPG) before removing the other plug from the SET (machine) jack. Pulling the SET jack first interrupts all TTY message traffic on that channel. IT ALSO PRODUCES A DANGEROUS DC VOLTAGE ON THE EXPOSED PLUG!"
>
>
> Nick England K4NYW
> www.navy-radio.com
>
>
>
>
>
>
>
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