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Bill,
The Trx SWR should be close to 1 with a 50 Ohm dummyload at the ATU Ant connector.
So imho there must be a short or open connection between the ATU Trx and Ant connector.
Maybe try with an Ohmmeter for a short or open circuit, but disconnect the Tandem Match cores first.
73, Nanko
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Mine only had 9 turns on it.
Bill
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Have the tandem match unwound at the moment.? Going to have to round up some wire.
Bill
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On Monday, November 11, 2024 at 02:12:24 AM CST, Nanko van Dijk via groups.io <nanko@...> wrote:
Bill,
If not already tried, if you terminate the ATU Ant connector with a 50 Ohm dummyload, what VSWR does your Trx show on transmit?
If your Trx doesn¡¯t have vswr, put one in between your trx and atu.
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hi Bill,
I don't know what case on your AT, but I've seen many ready built ATs with 11turns on the core... Perhaps also yours. So you can reuse the wires... You only? need 10 turns! that makes abt 1/2inch spare wire on each...?
For the input wire you just can use any bare wire. Must just fit to the soldering points and must not get contact to the secondary turns in any case. I prefer insulated wires or like described pieces of coax cable, with one side screen grounded!
73, Immo
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Hi , just a thought, why don't you use a PSU and inject a small voltage 3-4 volt in to the pins of the pic were the diodes were connected to, and see
If you get a reading on the display, if no reading you know you need a new pic,
Dave 2E0DMB
hi Bill,
some possibilities:
a) if a short winding is on the core (short in itself) the core gets high impedance! Perhaps some of the the windings were short (over the edges of the core) and to ground.
b) now not yet testable: a short from one secondary to ground (under the core)
c) a tiny solderbridge on one of the solderpads to ground (most preferred) moved in place through mechanical stress
73, Immo
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Thanks again Immo!!
The input wires going through the binocular core were bare copper with not insulation, short possible?? The windings were insulated wire.? I will rebuild it using your example.
Bill
On Monday, November 11, 2024 at 10:53:14 AM CST, Immo, DL5KB <dl5kb@...> wrote:
hi Bill,
some possibilities:
a) if a short winding is on the core (short in itself) the core gets high impedance! Perhaps some of the the windings were short (over the edges of the core) and to ground.
b) now not yet testable: a short from one secondary to ground (under the core)
c) a tiny solderbridge on one of the solderpads to ground (most preferred) moved in place through mechanical stress
73, Immo
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hi Bill,
some possibilities:
a) if a short winding is on the core (short in itself) the core gets high impedance! Perhaps some of the the windings were short (over the edges of the core) and to ground.
b) now not yet testable: a short from one secondary to ground (under the core)
c) a tiny solderbridge on one of the solderpads to ground (most preferred) moved in place through mechanical stress
73, Immo
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So essentially the input side tests, ok?? Now I am really confused.? I was hoping the short was there.?? Bill
On Monday, November 11, 2024 at 09:59:24 AM CST, Immo, DL5KB <dl5kb@...> wrote:
That all looks to be like it should.
:-)
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That all looks to be like it should.
:-)
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I just got all the windings pulled out of T1 and T2 and didn't find any issues.??
?
What did you think about my continuity readings?
Bill
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hi Bill,
I used 0.5mm enameled copper wire. #24AWG also #26AWG may suit. As inner winding I used a piece of RG174 whose shielding is connected at one side to ground. For making it easy to wind, I used a double sided adhesive tape wound around the core to hold the windings easy on place while winding. At last the ready cut piece of RG174 holds all wires on place. (see foto)
?
If you want to use the AT for power up to 100W, make 10 windings (note: every wire through the core is one winding. At the outer side you see only 9 wires while 10 windings are present.)
?
Only to mention it:
For use up to 40W you can wind only 5 turns and tuning will start with min. 2W. Then you have to adapt the cell? 05 to 02 for 2W tuning start and cell 31 to 05 for 5 turns on core... Tuning works better at low power levels,?displayed power is more accurate at low levels.
?
Good luck
73, Immo
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I desoldered as you picture instructed.? No continuity between Input and ground now.? There is continuity between input and output.? The windings on the T1 and T2 have no continuity with the solid wire that goes through the core.
?
Going to have to rewind T2.? The tiny wires broke.? What is the best sized wire to use?
?
Bill
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Bill,
If not already tried, if you terminate the ATU Ant connector with a 50 Ohm dummyload, what VSWR does your Trx show on transmit?
If your Trx doesn¡¯t have vswr, put one in between your trx and atu.
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resolder these ends, so ground stays on the secondary windings
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Thanks Dave!! ?Got a lot of investigating to do.
If nothing else I am sure learning a lot about the ATU-100 and troubleshooting it.
On Sunday, November 10, 2024, 3:01 PM, Dave (G8PTN) via groups.io <daveg8ptn@...> wrote: Hi Bill,
?
At DC, since the SWR bridge will look like a short circuit to ground, then all contacts of relay S8 will also look like a short to ground.
A simplified diagram is shown below.
?
Perhaps, if you do a base line measurement with the oscilloscope and your transmitter directly into a 50? dummy load (without the ATU-100).
You only need to use a low power to see a reasonable signal level on the oscilloscope.
The test frequency needs to be between say 3.5MHz and 30MHz and a CW carrier.
The peak to peak voltage into a 50? dummy load = SQRT(PWR x 50?) x SQRT(2) * 2
10 W = 63.2 V p-p, 5W = 44.7V p-p, 1W = 20V p-p
?
With the ATU-100 in line (50? dummy load on ATU output) and all relays ¡°OFF¡±, you should see the same voltage on both ports of the ATU-100.
?
If all this seems to work, you should then be able to measure the DC voltage on the outputs of the SWR bridge.
For a 10:1 bridge ratio, as per the diagram from Immo, the voltage should be around 2.5V on the (FWD) diode Cathode.
?
Reading through the thread, there appears to be something wrong if the OLED is stuck on the start up splash screen.
I have had a quick look at the firmware and I can't see why it would remain in that state.
I would not expect the tuner to do anything whilst in this state.
?
73, Dave
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Hi Bill,
?
At DC, since the SWR bridge will look like a short circuit to ground, then all contacts of relay S8 will also look like a short to ground.
A simplified diagram is shown below.
?
Perhaps, if you do a base line measurement with the oscilloscope and your transmitter directly into a 50? dummy load (without the ATU-100).
You only need to use a low power to see a reasonable signal level on the oscilloscope.
The test frequency needs to be between say 3.5MHz and 30MHz and a CW carrier.
The peak to peak voltage into a 50? dummy load = SQRT(PWR x 50?) x SQRT(2) * 2
10 W = 63.2 V p-p, 5W = 44.7V p-p, 1W = 20V p-p
?
With the ATU-100 in line (50? dummy load on ATU output) and all relays ¡°OFF¡±, you should see the same voltage on both ports of the ATU-100.
?
If all this seems to work, you should then be able to measure the DC voltage on the outputs of the SWR bridge.
For a 10:1 bridge ratio, as per the diagram from Immo, the voltage should be around 2.5V on the (FWD) diode Cathode.
?
Reading through the thread, there appears to be something wrong if the OLED is stuck on the start up splash screen.
I have had a quick look at the firmware and I can't see why it would remain in that state.
I would not expect the tuner to do anything whilst in this state.
?
73, Dave
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Thanks for the update. ?I will try that.
On Sunday, November 10, 2024, 2:52 PM, Immo, DL5KB <dl5kb@...> wrote: after desoldering one end of both secondaries only the wire through the binocular can make an unwanted short to primary signal path.?
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after desoldering one end of both secondaries only the wire through the binocular can make an unwanted short to primary signal path.?
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Immo, DL5KB
