Look at the front board of the High Pass Filter module. On the back side you will find a lone push pin connector near the edge of the board and near the top corner where the chassis ground strap is attached. It is also very near where the plug-in coax connects. Photo attached. On Sat, 01 Feb 2025 17:39:02 -0800 "Mike Davidsohn G3ZCC via groups.io" <mike@...> wrote: Also found the wire which goes to the DR7, laying inside.
I know the connection to the DR7? but not to the HPF board assembly.
Any pictures showing this?. -- 73 -Jim NU0C
|
Hi everyone, thanks for your help.
they say don't work on a radio tired.
Well it was the PBT button pressed.
Signs of life now, but the cal seems weak.
On 7 mhz it is a little noisy and the S meter barely makes S9 (S METER adjusted as per manual).
Gets markedly weaker as you go HF.
Going to put a known 50uv signal in the antenna socket tommorrow and see how that compares.
Hope it's not a Pin diode.
?
Also found the wire which goes to the DR7, laying inside.
I know the connection to the DR7? but not to the HPF board assembly.
Any pictures showing this?.
That's where I'm at right now.
Kind Regards
Mike
G3ZCC
?
?
|
Re: L7 power amplifier question
MY mistake, I apologize. ? That is what I measured a few years ago before installing the soft key.
24-28vdc is what I measure on mine. ?If you want specifics out to two or three decimal places I can do that for you.
73,
Evan, K9SQG
Dave,
I don't have one here to measure. Research reveals zilch. So I'd
just like to know open voltage at the jack and key loop current of
an original L7 if anyone happens to know conclusively.
Thanks,
Jim WA9Z
?
.?
Jim WA9Z
You can
just measure it, but if it helps, YES...it is above the limit
on most rigs, and will need an external relay.? I went through
this once myself!?
....Dave
On 02/01/2025 1:51 PM EST Jim WA9Z
<jim@...> wrote: ?
?
Howdy guys,
I would like to know what normal open voltage and key
current is at the VOX RELAY jack is on the L7.
Thank-you,
Jim WA9Z
??
|
Re: L7 power amplifier question
24-28vdc is what I measure on mine. ?If you want specifics out to two or three decimal places I can do that for you.
73,
Evan, K9SQG
Dave,
I don't have one here to measure. Research reveals zilch. So I'd
just like to know open voltage at the jack and key loop current of
an original L7 if anyone happens to know conclusively.
Thanks,
Jim WA9Z
?
.?
Jim WA9Z
You can
just measure it, but if it helps, YES...it is above the limit
on most rigs, and will need an external relay.? I went through
this once myself!?
....Dave
On 02/01/2025 1:51 PM EST Jim WA9Z
<jim@...> wrote: ?
?
Howdy guys,
I would like to know what normal open voltage and key
current is at the VOX RELAY jack is on the L7.
Thank-you,
Jim WA9Z
??
|
Re: L7 power amplifier question
Dave,
I don't have one here to measure. Research reveals zilch. So I'd
just like to know open voltage at the jack and key loop current of
an original L7 if anyone happens to know conclusively.
Thanks,
Jim WA9Z
?
.?
Jim WA9Z
toggle quoted message
Show quoted text
You can
just measure it, but if it helps, YES...it is above the limit
on most rigs, and will need an external relay.? I went through
this once myself!?
....Dave
On 02/01/2025 1:51 PM EST Jim WA9Z
<jim@...> wrote: ?
?
Howdy guys,
I would like to know what normal open voltage and key
current is at the VOX RELAY jack is on the L7.
Thank-you,
Jim WA9Z
??
|
Re: successQ multiplier cable
Excellent!
Yes, the 455 kHz wiring between the receiver and the multiplier was simple multiconductor cable.? It may be shielded but I'd have to take the 2-BQ apart to know for sure.? RG-174 is certainly a fine cable for this.
I'm still waiting for my Round Tuit to arrive to wire up my 1-A and 2-B to a spare T-4XB (I have two working spares, at the moment).
Enjoy!
Steve Wedge, W1ES
Time flies like an arrow.? Fruit flies like a banana.
Sent with secure email.
On Saturday, February 1st, 2025 at 3:22 PM, Paul N5NEN via groups.io <n5nen@...> wrote:
The QF-1 to a Drake 2A ?adapted and working as it should. ?Maybe any 4wire cable would do. I used old heath power cable and a rg174 coax for the IF. 
|
Thanks Jim for the info and I will try and get back at it tomorrow.?
73, Jim VE1RB
Yes, you want to look at the 2nd IF/Audio board. CW operation is described towards the end of the text in section 2-11 of the service manual. In short the CW transmit carrier is generated by a crystal oscillator that is offset nominally 800 Hz from the dial frequency. The oscillator is keyed by Q1103 on this board.
More info on the oscillator is here:
On Sat, 1 Feb 2025 14:17:50 -0400
"Jim Harris via " <radiove1rb=[email protected]> wrote:
> Hi once again. I am back trouble shooting the TR7 with what I hope is the
> last problem. When I switch the mode switch to CW I get a 1800 cycle tone
> in the receiver that is over S9 in strength. If you change the frequency
> this tone does not change at all. I have a Version 2, 2nd I.F/Audio board.
> I have not found an explanation of how the CW operation works but maybe the
> problem is on that board. Anyone got any ideas? All suggestions appreciated
> and welcomed.
> Thank you, Jim VE1RB
--
73
-Jim
NU0C
|
Re: successQ multiplier cable
The QF-1 to a Drake 2A ?adapted and working as it should. ?Maybe any 4wire cable would do. I used old heath power cable and a rg174 coax for the IF. 
|
Re: L7 power amplifier question
I believe I've measured 24-28 vdc but don't remember the current. ?Issues are voltage, current, and inductive spike. ?I've install a RadioGadgets ?UKA-1 I believe, inside the L4B and L7s that I have. ?The adaptor is small, reasonably priced, has an opto-isolator on the key line, can be powered by the amp, and can handle several hundred volts at "high" current, and only presents about 5-7 vdc at a few mills on the keying line. ?Installation is described in one of the Drake Forums listed at the WB4HFN website. ?
About 30-35VDC
My IC-7610 has no problem with that as long as I use the FET switch but most SS rigs won¡¯t do well with that. Those rigs will need an interface.?
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Sat, Feb 1, 2025 at 13:58, Dave Edwards via groups.io < kd2e@...> wrote:
You can just measure it, but if it helps, YES...it is above the limit on most rigs, and will need an external relay.? I went through this once myself!?
....Dave
On 02/01/2025 1:51 PM EST Jim WA9Z <jim@...> wrote:
?
?
Howdy guys,
I would like to know what normal open voltage and key current is at the VOX RELAY jack is on the L7.
Thank-you,
Jim WA9Z
??
|
Re: L7 power amplifier question
About 30-35VDC
My IC-7610 has no problem with that as long as I use the FET switch but most SS rigs won¡¯t do well with that. Those rigs will need an interface.?
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Sat, Feb 1, 2025 at 13:58, Dave Edwards via groups.io < kd2e@...> wrote:
You can just measure it, but if it helps, YES...it is above the limit on most rigs, and will need an external relay.? I went through this once myself!?
....Dave
On 02/01/2025 1:51 PM EST Jim WA9Z <jim@...> wrote:
?
?
Howdy guys,
I would like to know what normal open voltage and key current is at the VOX RELAY jack is on the L7.
Thank-you,
Jim WA9Z
??
|
Re: L7 power amplifier question
You can just measure it, but if it helps, YES...it is above the limit on most rigs, and will need an external relay.? I went through this once myself!?
....Dave
On 02/01/2025 1:51 PM EST Jim WA9Z <jim@...> wrote:
?
?
Howdy guys,
I would like to know what normal open voltage and key current is at the VOX RELAY jack is on the L7.
Thank-you,
Jim WA9Z
??
|
L7 power amplifier question
Howdy guys,
I would like to know what normal open voltage and key current is at the VOX RELAY jack is on the L7.
Thank-you,
Jim WA9Z
??
|
Yes, you want to look at the 2nd IF/Audio board. CW operation is described towards the end of the text in section 2-11 of the service manual. In short the CW transmit carrier is generated by a crystal oscillator that is offset nominally 800 Hz from the dial frequency. The oscillator is keyed by Q1103 on this board. More info on the oscillator is here: On Sat, 1 Feb 2025 14:17:50 -0400 "Jim Harris via groups.io" <radiove1rb@...> wrote: Hi once again. I am back trouble shooting the TR7 with what I hope is the
last problem. When I switch the mode switch to CW I get a 1800 cycle tone
in the receiver that is over S9 in strength. If you change the frequency
this tone does not change at all. I have a Version 2, 2nd I.F/Audio board.
I have not found an explanation of how the CW operation works but maybe the
problem is on that board. Anyone got any ideas? All suggestions appreciated
and welcomed.
Thank you, Jim VE1RB -- 73 -Jim NU0C
|
Hi once again. I am back trouble shooting the TR7 with what I hope is the last problem. When I switch the?mode switch?to CW I get a 1800 cycle tone in the receiver that is over S9 in strength. If you change the frequency this tone does not change at all. I have a Version 2, 2nd I.F/Audio board. I have not found an explanation?of how the CW operation works but maybe the problem is on that board. Anyone got any ideas? All suggestions appreciated and welcomed. Thank you, Jim VE1RB
|
Recently had a similar issue where the PBT pots on the power supply board were non-functional; problem turned out to be internal PBT switch leakage to the lamp circuit, which was offering a low-z path to gnd and affecting both RX and TX. Pin 27 of the PBT board is where that voltage is "sent" based on the mode switch.?
--
Craig/W8CS
Greenville, SC
|
Thanks Steve, with your help I may be able to make this Drake R-4B sing again. Steve there are no problems with package delivery in Italy. Poste Italiane are working well. I regularly receive shipments from China and all European countries. If you can send me the T11 in a padded envelope and let me know the total expense of the T11 + shipping I will arrange to send you the money via Paypal or bank transfer to your account. Let me know if the operation is possible. Best regards Matteo ik2gsr
?
|
The passband tuning voltages are steered by quad analog switch IC U1001 on the PBT/Reference board. If the control signals are reaching the IC and it is not switching as it should it has likely failed. It is a CMOS 4016 IC and they area known problem area. On Fri, 31 Jan 2025 18:22:46 -0800 "Mike Davidsohn G3ZCC via groups.io" <mike@...> wrote: Hi everyone.
Made great progress, all alignment looked fine until I got to the bandpass tuning pots on the power supply board, moving them all, nothing happened, 10v adjust ok.
Took the board out, cleaned the molex connectors, resoldered a few iffy joints and replaced.
Still the same, putting my meter on the centre pin of each pot I adjusted them to 6.1 volts each as a diagnostic tool.
Turned the TR7 over and measured all the pins on the socket, wr to earth.
All fine, the 6.1v appeared on each required pin.
Looking in the manual it's very blurred on the wiring diagram.
Before I trace every wire, has anyone got any idea on the link to the PBT board.
The fact that all modes has this fault may be the clue that is going over my head.
Thanks
Mike
G3ZCC -- 73 -Jim NU0C
|
Just making sure: you don¡¯t have the PBT button pushed in, right? ?BTDT
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Fri, Jan 31, 2025 at 21:22, Mike Davidsohn G3ZCC via groups.io < mike@...> wrote:
Hi everyone.
Made great progress, all alignment looked fine until I got to the bandpass tuning pots on the power supply board, moving them all, nothing happened, 10v adjust ok.
Took the board out, cleaned the molex connectors, resoldered a few iffy joints and replaced.
Still the same, putting my meter on the centre pin of each pot I adjusted them to 6.1 volts each as a diagnostic tool.
Turned the TR7 over and measured all the pins on the socket, wr to earth.
All fine, the 6.1v appeared on each required pin.
Looking in the manual it's very blurred on the wiring diagram.
Before I trace every wire, has anyone got any idea on the link to the PBT board.
The fact that all modes has this fault may be the clue that is going over my head.
Thanks
Mike
G3ZCC
?
|
Hi everyone.
Made great progress, all alignment looked fine until I got to the bandpass tuning pots on the power supply board, moving them all, nothing happened, 10v adjust ok.
Took the board out, cleaned the molex connectors, resoldered a few iffy joints and replaced.
Still the same, putting my meter on the centre pin of each pot I adjusted them to 6.1 volts each as a diagnostic tool.
Turned the TR7 over and measured all the pins on the socket, wr to earth.
All fine, the 6.1v appeared on each required pin.
Looking in the manual it's very blurred on the wiring diagram.
Before I trace every wire, has anyone got any idea on the link to the PBT board.
The fact that all modes has this fault may be the clue that is going over my head.
Thanks
Mike
G3ZCC
?
|
I have one but am not sure about what would be involved with shipping. ?Are there still issues with sending parcels to Italy? ?
Steve Wedge, W1ES
Time flies like an arrow. Fruit flies like a banana.
On Fri, Jan 31, 2025 at 4:44 PM, Dave W7GZ via groups.io < w7gz@...> wrote:
Matteo, you are not crazy but you must be determined. The distortion tells me something is amiss with the AGC system -- incorrect AGC voltage or bad interstage coupling caps putting B+ on the grids.
?
As for T11, the easiest way is to watch eBay for the part to show up. You can certainly build a new coil, or perhaps adapt a new part that you find with Google, but that will be more work.
?
Good luck, and keep us posted.
?
Dave
|
Jim Shorney
Mike Davidsohn G3ZCC
Craig W8CS