OK everyone,
I am finally starting to look into the TR-3 in depth as has been suggested
I have received the replacement caps from Hayseed Hamfest for my TR-3.
The original can is still in place.
I will replace the can this weekend instead of playing in the new fallen snow.
I have yet to find where the small 10uf is. Can someone give me an idea where this cap is?
What style tubular cap is on the stand up boards?
Should they be replaced?
I do not have a capacitor checker.
I have randomly measured some resistors in circuit and there are some that are off value.
What is the preferred replacement style resistor?
Any other suggestions.
Thanks much,
Dave KC3AM
|
Not sure but good point.?
I used to disconnect the 9V battery when I wasn¡¯t using it but have discovered that I¡¯ll get at least a year out of a battery even if I just leave it, so that¡¯s how I¡¯m doing it now.?
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
On Fri, Jan 19, 2024 at 09:49, Dan < pitfit@...> wrote: ?Curious if your bad experience was with a switching or linear wall wart???
Dan WB4GRA On Jan 19, 2024, at 9:22?AM, Steve Wedge, W1ES/4 via groups.io <w1es@...> wrote:
? I will no longer use any wall warts to supply DC to anything that¡¯s sensitive. I learned the hard way with one of my old Trac CMOS keyers. I had to replace all eight chips and a transistor when the wart failed.?
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
On Thu, Jan 18, 2024 at 21:45, Evan via groups.io < k9sqg@...> wrote:
As to DC ?wall cubes, test first. ?Some of them have high onset voltage until the regulator kicks in, and some of them are prone to RFI altering the output voltage.
On Thursday, January 18, 2024 at 02:17:48 PM EST, Paul Christensen <w9ac@...> wrote:
I¡¯ll soon be installing a K4DPK VFO stabilizer in my TR-4Cw.? The stabilizer works on 10-14 VDC.? Since there¡¯s no low voltage in the TR-4Cw, I¡¯m curious how others have attempted the supply voltage dilemma,.? Here are some options: ? - Use the 12.6VAC filament line and use a well filtered half-wave rectifier and Zener diode.? The stabilizer draws relatively low current so ripple shouldn¡¯t be too difficult to manage;
- Use a filtered full-wave bridge rectifier on the 12.6VAC line for better ripple suppression. ?Note that one side of the 12.6VAC winding from the AC-4 power supply is grounded/bonded to the chassis.? As such, a standard two-diode full wave rectifier isn¡¯t easily managed here;
- Or as Drake engineers loved, consider hot, power-hungry wire wound resistors to drop voltage on one of the B+ lines.? Frankly, it¡¯s not an option to add even more cabinet heat to a problem that is heat generated in the first place;
- External DC wall cube.? This throw-in-the-towel solution and #3 above just aren¡¯t viable for me.? ?
? Other options come to mind?? I¡¯m not keen on anything that uses DC-DC switching regulators no matter how well they¡¯re filtered.? ? Paul, W9AC
|
? Curious if your bad experience was with a switching or linear wall wart???
Dan WB4GRA
toggle quoted message
Show quoted text
On Jan 19, 2024, at 9:22?AM, Steve Wedge, W1ES/4 via groups.io <w1es@...> wrote:
? I will no longer use any wall warts to supply DC to anything that¡¯s sensitive. I learned the hard way with one of my old Trac CMOS keyers. I had to replace all eight chips and a transistor when the wart failed.?
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
On Thu, Jan 18, 2024 at 21:45, Evan via groups.io < k9sqg@...> wrote:
As to DC ?wall cubes, test first. ?Some of them have high onset voltage until the regulator kicks in, and some of them are prone to RFI altering the output voltage.
On Thursday, January 18, 2024 at 02:17:48 PM EST, Paul Christensen <w9ac@...> wrote:
I¡¯ll soon be installing a K4DPK VFO stabilizer in my TR-4Cw.? The stabilizer works on 10-14 VDC.? Since there¡¯s no low voltage in the TR-4Cw, I¡¯m curious how others have attempted the supply voltage dilemma,.? Here are some options: ? - Use the 12.6VAC filament line and use a well filtered half-wave rectifier and Zener diode.? The stabilizer draws relatively low current so ripple shouldn¡¯t be too difficult to manage;
- Use a filtered full-wave bridge rectifier on the 12.6VAC line for better ripple suppression. ?Note that one side of the 12.6VAC winding from the AC-4 power supply is grounded/bonded to the chassis.? As such, a standard two-diode full wave rectifier isn¡¯t easily managed here;
- Or as Drake engineers loved, consider hot, power-hungry wire wound resistors to drop voltage on one of the B+ lines.? Frankly, it¡¯s not an option to add even more cabinet heat to a problem that is heat generated in the first place;
- External DC wall cube.? This throw-in-the-towel solution and #3 above just aren¡¯t viable for me.? ?
? Other options come to mind?? I¡¯m not keen on anything that uses DC-DC switching regulators no matter how well they¡¯re filtered.? ? Paul, W9AC
|
I will no longer use any wall warts to supply DC to anything that¡¯s sensitive. I learned the hard way with one of my old Trac CMOS keyers. I had to replace all eight chips and a transistor when the wart failed.?
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
On Thu, Jan 18, 2024 at 21:45, Evan via groups.io < k9sqg@...> wrote:
As to DC ?wall cubes, test first. ?Some of them have high onset voltage until the regulator kicks in, and some of them are prone to RFI altering the output voltage.
On Thursday, January 18, 2024 at 02:17:48 PM EST, Paul Christensen <w9ac@...> wrote:
I¡¯ll soon be installing a K4DPK VFO stabilizer in my TR-4Cw.? The stabilizer works on 10-14 VDC.? Since there¡¯s no low voltage in the TR-4Cw, I¡¯m curious how others have attempted the supply voltage dilemma,.? Here are some options: ? - Use the 12.6VAC filament line and use a well filtered half-wave rectifier and Zener diode.? The stabilizer draws relatively low current so ripple shouldn¡¯t be too difficult to manage;
- Use a filtered full-wave bridge rectifier on the 12.6VAC line for better ripple suppression. ?Note that one side of the 12.6VAC winding from the AC-4 power supply is grounded/bonded to the chassis.? As such, a standard two-diode full wave rectifier isn¡¯t easily managed here;
- Or as Drake engineers loved, consider hot, power-hungry wire wound resistors to drop voltage on one of the B+ lines.? Frankly, it¡¯s not an option to add even more cabinet heat to a problem that is heat generated in the first place;
- External DC wall cube.? This throw-in-the-towel solution and #3 above just aren¡¯t viable for me.? ?
? Other options come to mind?? I¡¯m not keen on anything that uses DC-DC switching regulators no matter how well they¡¯re filtered.? ? Paul, W9AC
|
>"Paul, what's the current requirement for that VFO stabilizer board? 73/jeff/ac0c"
Jeff,
No spec but the stabilizer has four CMOS chips and one LED with the LED drawing the most current.? So, 15-20 mA.? Either a 78L10 or 1/2W 10V Zener should be fine.? The 78Lxx devices are good to a max current of 100mA.? Rather than one 'lytic filter cap, I'll use four in parallel after the half-wave rectifier.
Paul, W9AC??
|
I'll take the filter. PM the details off line.
Tnx.?
On Thursday, January 18, 2024 at 03:36:17 PM EST, George Rybicki <atomant@...> wrote:
I have a used one I can let go for $50 if anyone still needs one. 
|
As to DC ?wall cubes, test first. ?Some of them have high onset voltage until the regulator kicks in, and some of them are prone to RFI altering the output voltage.
On Thursday, January 18, 2024 at 02:17:48 PM EST, Paul Christensen <w9ac@...> wrote:
I¡¯ll soon be installing a K4DPK VFO stabilizer in my TR-4Cw.? The stabilizer works on 10-14 VDC.? Since there¡¯s no low voltage in the TR-4Cw, I¡¯m curious how others have attempted the supply voltage dilemma,.? Here are some options: ? - Use the 12.6VAC filament line and use a well filtered half-wave rectifier and Zener diode.? The stabilizer draws relatively low current so ripple shouldn¡¯t be too difficult to manage;
- Use a filtered full-wave bridge rectifier on the 12.6VAC line for better ripple suppression. ?Note that one side of the 12.6VAC winding from the AC-4 power supply is grounded/bonded to the chassis.? As such, a standard two-diode full wave rectifier isn¡¯t easily managed here;
- Or as Drake engineers loved, consider hot, power-hungry wire wound resistors to drop voltage on one of the B+ lines.? Frankly, it¡¯s not an option to add even more cabinet heat to a problem that is heat generated in the first place;
- External DC wall cube.? This throw-in-the-towel solution and #3 above just aren¡¯t viable for me.? ?
? Other options come to mind?? I¡¯m not keen on anything that uses DC-DC switching regulators no matter how well they¡¯re filtered.? ? Paul, W9AC
|
Bob thank you again for your thoughts. The potentiometer did fail completely so I'm on the hunt fo a 15M linear potentiometer. Best I've found so far is 5M from mouser who should be fine. If anyone out there has another option please let me know.
For now, I had a 10k pot extra from the 2BQ repair that I soldered in today. Relay is back to normal operation for now and not getting stuck. The delay is obviously very quick, essentially QSK between letters. Hope the 5M will be enough range to lengthen the delay a bit more.
Joe ki5o?
|
Re: TR7 fails to PLL when turned on
Good point. The 78L24 is a known failure point. Also C2108, which causes strange problems when (not IF) it fails. Replace it if today is a day that ends in the letter Y. The -5 will be around -3 to -4 and is only used to back bias the PIN diodes on the IF filter board. 73 -Jim NU0C On Thu, 18 Jan 2024 13:05:59 -0800 "Steven KE2AXS" <sosborne8270@...> wrote: I had this same problem. Found the core fell out of the T2101 transformer on the power supply / regulator board. Found it in the bottom of my TR7. Tied that back in place and all was well. Check that you are really seeing a full 24VDC and about -5 VDC from that board. Strangely even with half the core laying in the bottom of the radio, it would work after about a 5 min warm up!
-- 73 -Jim NU0C
|
Paul, what's the current requirement for that VFO stabilizer board?
73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com
toggle quoted message
Show quoted text
On 1/18/2024 4:28 PM, Jim Shorney wrote: There are LDO versions of the 317 series. Fixed regulators can also benefit from a protection diode. The risk is if the input voltage falls below the output voltage. Diodes are cheap. I have a tendency to add one if I have to replace a regulator.
73
-Jim
NU0C
On Thu, 18 Jan 2024 15:25:49 -0500
"Paul Christensen" <w9ac@...> wrote:
Jim,
I don't believe the 317T is a low-drop-out regulator. There won't be much
In-Out margin on the 12.6 VAC string during a brown-out condition with
half-wave rectification. It also requires (or strongly suggested by the
OEMs) use of protection diodes across the I/O terminals and output.
Considering the low current draw and wide supply range of the K4DPK
stabilizer, 78L10 or 78L12 should be sufficient.
Paul, W9AC
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Jim Shorney
Sent: Thursday, January 18, 2024 3:10 PM
To: [email protected]
Subject: Re: [DRAKE-RADIO] K4DPK VFO Stabilizer
Even better, use a 317T regulator *with recommended external caps*. Better
specs and you can set the voltage to exactly what you want.
73
-Jim
NU0C
On Thu, 18 Jan 2024 11:52:15 -0800
"jerry-KF6VB" <jerry@...> wrote:
On 2024-01-18 11:17, Paul Christensen wrote:
I'll soon be installing a K4DPK VFO stabilizer in my TR-4Cw. The
stabilizer works on 10-14 VDC. Since there's no low voltage in the
TR-4Cw, I'm curious how others have attempted the supply voltage
dilemma, *** I had a similar requirement for my KWM-2. I used a half-wave
rectifier off the filament circuit, feeding a TO-92 three-terminal
regulator.
Which
has far better ripple rejection than a zener diode.
Actually, I wound up using two half-wave rectifier circuits; one for
a BHI noise reduction module inserted in the audio stream, and the
other for a DC fan.
In the case of the KWM2, there was an empty tube socket on the
chassis, meant for a noise blanker option. This had most of the
signals I needed, including a switch closure for the "NB" position on
the front panel. So now when I click to "NB", the band noise goes
down. I mostly leave it in "NB".
- Jerry, KF6VB
|
Also marketed as LED drivers. I have an adjustable one driving the +20v PLL power source in a Uniden scanner as the original dead chip was unobtanium at the time. It's been working well for a couple of years now. 73 -Jim NU0C On Thu, 18 Jan 2024 20:31:19 +0000 "nigel patterson G3YDT" <wnigelpatterson@...> wrote: There are very cheap DC to DC converters (sometimes called regulators or
step up or step down (buck) but are adjustable for output voltage) from
China on the internet, for $5. -- 73 -Jim NU0C
|
There are LDO versions of the 317 series. Fixed regulators can also benefit from a protection diode. The risk is if the input voltage falls below the output voltage. Diodes are cheap. I have a tendency to add one if I have to replace a regulator. 73 -Jim NU0C On Thu, 18 Jan 2024 15:25:49 -0500 "Paul Christensen" <w9ac@...> wrote: Jim,
I don't believe the 317T is a low-drop-out regulator. There won't be much
In-Out margin on the 12.6 VAC string during a brown-out condition with
half-wave rectification. It also requires (or strongly suggested by the
OEMs) use of protection diodes across the I/O terminals and output.
Considering the low current draw and wide supply range of the K4DPK
stabilizer, 78L10 or 78L12 should be sufficient.
Paul, W9AC
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Jim Shorney
Sent: Thursday, January 18, 2024 3:10 PM
To: [email protected]
Subject: Re: [DRAKE-RADIO] K4DPK VFO Stabilizer
Even better, use a 317T regulator *with recommended external caps*. Better
specs and you can set the voltage to exactly what you want.
73
-Jim
NU0C
On Thu, 18 Jan 2024 11:52:15 -0800
"jerry-KF6VB" <jerry@...> wrote:
On 2024-01-18 11:17, Paul Christensen wrote:
I'll soon be installing a K4DPK VFO stabilizer in my TR-4Cw. The
stabilizer works on 10-14 VDC. Since there's no low voltage in the
TR-4Cw, I'm curious how others have attempted the supply voltage
dilemma, *** I had a similar requirement for my KWM-2. I used a half-wave
rectifier off the filament circuit, feeding a TO-92 three-terminal
regulator.
Which
has far better ripple rejection than a zener diode.
Actually, I wound up using two half-wave rectifier circuits; one for
a BHI noise reduction module inserted in the audio stream, and the
other for a DC fan.
In the case of the KWM2, there was an empty tube socket on the
chassis, meant for a noise blanker option. This had most of the
signals I needed, including a switch closure for the "NB" position on
the front panel. So now when I click to "NB", the band noise goes
down. I mostly leave it in "NB".
- Jerry, KF6VB
-- 73 -Jim NU0C
|
Re: Misc parts at NC0B's QTH
Maybe. It is a hermetic I/O pin. If you want it for $25 it is yours.
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Lyndon VE7TFX Sent: Thursday, January 18, 2024 10:49 AM To: [email protected]; Rob Sherwood. Subject: Re: [DRAKE-RADIO] Misc parts at NC0B's QTH Rob Sherwood writes: CF-2K/16 w/ bracket Sherwood $100 Rob, regarding that filter, even though the pin has broken off, it should be repairable? Assuming I can get the cover off it, it should be possible to solder in a replacement pin, no? If you think that's feasable, I'd be willing to buy the filter (at a bit of a discount) and take a shot at MacGyvering it back to life. Cheers, --lyndon
|
Re: TR7 fails to PLL when turned on
I had this same problem. Found the core fell out of the T2101 transformer on the power supply / regulator board. Found it in the bottom of my TR7. Tied that back in place and all was well. Check that you are really seeing a full 24VDC and about -5 VDC from that board. Strangely even with half the core laying in the bottom of the radio, it would work after about a 5 min warm up!
|
Nigel, ? I would like to avoid switching/bucking DC-DC regulators.? Sometimes they seem fine only to discover a spur or two some time after a mod is made. ? Just me, but I think all vacuum tube gear should run without grounded heater returns.? In audio stages, it¡¯s so much easier to balance out hum that way.? ? Yes, it¡¯s possible to un-ground the heaters but have a look at the collision of parts and wiring under a TR-4Cw.? Adding a dedicated wiring string for the heater return on all tubes would be a nightmare.? ? Paul, W9AC ?
toggle quoted message
Show quoted text
From: [email protected] < [email protected]> On Behalf Of nigel patterson G3YDT Sent: Thursday, January 18, 2024 3:31 PM To: [email protected]Subject: Re: [DRAKE-RADIO] K4DPK VFO Stabilizer ? I have not read the other suggestions, but two come to mind 1. Can you unground one side of the AC for heaters.? Normally it is a twisted pair.? I used a bridge to pull down the heater voltage on a R4C from 7.0 to 6.5. (It had forfeited some tubes for transistors) 2. There are very cheap DC to DC converters (sometimes called regulators or step up or step down (buck) but are adjustable for output voltage) from China on the internet, for $5.? So rectify your heater voltage - half wave may be OK.? The two sides of the converter are electrically isolated. I used one also on a drake R2C using a replacement mains transformer that did not have a 12.6V output.? So boosted from 6.3V.? If there is interference put the ferrite beads on the wires. ? On Thu, Jan 18, 2024 at 8:09?PM Jim Shorney <jimNU0C@...> wrote:
Even better, use a 317T regulator *with recommended external caps*. Better specs and you can set the voltage to exactly what you want.
73
-Jim
NU0C
On Thu, 18 Jan 2024 11:52:15 -0800
"jerry-KF6VB" <jerry@...> wrote:
> On 2024-01-18 11:17, Paul Christensen wrote:
> > I'll soon be installing a K4DPK VFO stabilizer in my TR-4Cw.? The
> > stabilizer works on 10-14 VDC.? Since there's no low voltage in the
> > TR-4Cw, I'm curious how others have attempted the supply voltage
> > dilemma,?
>
> *** I had a similar requirement for my KWM-2.? I used a half-wave
> rectifier
> off the filament circuit, feeding a TO-92 three-terminal regulator.?
> Which
> has far better ripple rejection than a zener diode.
>
> Actually, I wound up using two half-wave rectifier circuits;? one for
> a BHI noise reduction module inserted in the audio stream, and the other
> for a DC fan.
>
>? ? In the case of the KWM2, there was an empty tube socket on the
> chassis,
> meant for a noise blanker option.? This had most of the signals I
> needed,
> including a switch closure for the "NB" position on the front panel.? So
> now when I click to "NB", the band noise goes down.? I mostly leave it
> in
> "NB".
>
>? ? ? ? ? ? ? ? ? ?- Jerry, KF6VB
>
>
>
>
>
--
73
-Jim
NU0C
|
I have a used one I can let go for $50 if anyone still needs one. 
|
Paul
I have not read the other suggestions, but two come to mind
1. Can you unground one side of the AC for heaters.? Normally it is a twisted pair.? I used a bridge to pull down the heater voltage on a R4C from 7.0 to 6.5. (It had forfeited some tubes for transistors)
2. There are very cheap DC to DC converters (sometimes called regulators or step up or step down (buck) but are adjustable for output voltage) from China on the internet, for $5.? So rectify your heater voltage - half wave may be OK.? The two sides of the converter are electrically isolated.
I used one also on a drake R2C using a replacement mains transformer that did not have a 12.6V output.? So boosted from 6.3V.? If there is interference put the ferrite beads on the wires.
Nigel
On Thu, Jan 18, 2024 at 8:09?PM Jim Shorney < jimNU0C@...> wrote:
Even better, use a 317T regulator *with recommended external caps*. Better specs and you can set the voltage to exactly what you want.
73
-Jim
NU0C
On Thu, 18 Jan 2024 11:52:15 -0800
"jerry-KF6VB" <jerry@...> wrote:
> On 2024-01-18 11:17, Paul Christensen wrote:
> > I'll soon be installing a K4DPK VFO stabilizer in my TR-4Cw.? The
> > stabilizer works on 10-14 VDC.? Since there's no low voltage in the
> > TR-4Cw, I'm curious how others have attempted the supply voltage
> > dilemma,?
>
> *** I had a similar requirement for my KWM-2.? I used a half-wave
> rectifier
> off the filament circuit, feeding a TO-92 three-terminal regulator.?
> Which
> has far better ripple rejection than a zener diode.
>
> Actually, I wound up using two half-wave rectifier circuits;? one for
> a BHI noise reduction module inserted in the audio stream, and the other
> for a DC fan.
>
>? ? In the case of the KWM2, there was an empty tube socket on the
> chassis,
> meant for a noise blanker option.? This had most of the signals I
> needed,
> including a switch closure for the "NB" position on the front panel.? So
> now when I click to "NB", the band noise goes down.? I mostly leave it
> in
> "NB".
>
>? ? ? ? ? ? ? ? ? ?- Jerry, KF6VB
>
>
>
>
>
--
73
-Jim
NU0C
|
Jim,
I don't believe the 317T is a low-drop-out regulator. There won't be much
In-Out margin on the 12.6 VAC string during a brown-out condition with
half-wave rectification. It also requires (or strongly suggested by the
OEMs) use of protection diodes across the I/O terminals and output.
Considering the low current draw and wide supply range of the K4DPK
stabilizer, 78L10 or 78L12 should be sufficient.
Paul, W9AC
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] < [email protected]> On Behalf Of Jim Shorney Sent: Thursday, January 18, 2024 3:10 PM To: [email protected]Subject: Re: [DRAKE-RADIO] K4DPK VFO Stabilizer Even better, use a 317T regulator *with recommended external caps*. Better specs and you can set the voltage to exactly what you want. 73 -Jim NU0C On Thu, 18 Jan 2024 11:52:15 -0800 "jerry-KF6VB" <jerry@...> wrote: On 2024-01-18 11:17, Paul Christensen wrote:
I'll soon be installing a K4DPK VFO stabilizer in my TR-4Cw. The
stabilizer works on 10-14 VDC. Since there's no low voltage in the
TR-4Cw, I'm curious how others have attempted the supply voltage
dilemma, *** I had a similar requirement for my KWM-2. I used a half-wave
rectifier off the filament circuit, feeding a TO-92 three-terminal
regulator.
Which
has far better ripple rejection than a zener diode.
Actually, I wound up using two half-wave rectifier circuits; one for
a BHI noise reduction module inserted in the audio stream, and the
other for a DC fan.
In the case of the KWM2, there was an empty tube socket on the
chassis, meant for a noise blanker option. This had most of the
signals I needed, including a switch closure for the "NB" position on
the front panel. So now when I click to "NB", the band noise goes
down. I mostly leave it in "NB".
- Jerry, KF6VB
-- 73 -Jim NU0C
|
On 2024-01-18 12:06, Paul Christensen wrote: Jerry,
You probably used a 78L12? *** That sounds about right. And now that I remember, I used a 1/2 wave voltage doubler running off the 6.3VAC. - Jerry, KF6VB
|
Re: TR7 fails to PLL when turned on
Check the RV7 Jones plug and socket, front panel Fixed buttons, and "Molexia" on the other boards. 73 -Jim NU0C On Thu, 18 Jan 2024 11:54:01 -0800 "K6OXN Bob" <bobk6oxn@...> wrote: My TR7 even with an NRV7 fails to lock the displayed freq when turned on. Have to cycle the on/off a few times or cycle the AUX7 switch. I have cleaned and checked all connections to the DR7 and on the AUX switch and ON/OFF without any luck.? Any other suggestions.
73? Bob
-- 73 -Jim NU0C
|
Paul Christensen
Jim Shorney
Rob Sherwood