DRAKE-RADIO@groups.io | Tr7. 10T (2024)

Looks like the 10T is acting up. In transmit less than 1.5 volts on the ALC I.C. Assuming a bypass capacitor may have taken out transistors in the transmit exciter board. Or something is pulling the voltage down. What is the 10T bus attached to? Exciter board and the ALC board and what else? Thought I'd change all the 10T caps.

73's

It's probably easier to tell you where the +10T does NOT go. Not to the Digital Control board, VCO board, Translator board, Power Supply board, AUX-7 (unless you are using Fixed ctystal controlled transmit), DR-7, or PA module.

The T/R switching transistors are the three-legged fuses on the TR-7. They will pop from even an instantaneous short to ground of the T or R line. But you could also have dirty/oxidized Molex connectors. Try re-seating the TX Exciter board first.

73

-Jim
NU0C

On Sun, 25 Feb 2018 14:06:28 +0000 (UTC), Ray Collins raycollins39@... [DrakeRadio] wrote:

Looks like the 10T is acting up. In transmit less than 1.5 volts on the ALC I.C.Assuming a bypass capacitor may have taken out transistors in the transmit exciter board. Or something is pulling the voltage down. What is the 10T bus attached to? Exciter board and the ALC board and what else? Thought I'd change all the 10T caps.
73's
Ray VE3BDK

--
“There’s something out of place – let’s go and poke it with a stick.” – The Doctor, "Amy’s Choice"

Thanks Jim, I'm assuming the 10t is generated in the Transmitter exciter card? The radio has receive and the relay clicks over. I've changed all the caps on the exciter card, not looking forward to pulling the transistors. The boards been in and out a few times and deoxit applied.

73

The 10v comes from the power supply board and goes to the transmitexciter board. Transistors Q306 transmit and Q307 receive, both are2N4402, are the switches. They act as fuses when anything shortseither 10 volt rail.

73, Joe Pyles KC9LAD

At 09:47 AM 2/26/2018, you wrote:

Â

Thanks Jim, I'm assuming the 10t is generated in the Transmitter excitercard? The radio has receive and the relay clicks over. I've changed allthe caps on the exciter card, not looking forward to pulling thetransistors. The boards been in and out a few times and deoxitapplied.

73
Ray VE3BDK

Sent from Yahoo Mail foriPad

On Sunday, February 25, 2018, 12:50 PM, 'Jim Shorney'jshorney@... [DrakeRadio] wrote:

See Also

CBSE Result 2024 Live: Latest updates on CBSE Class 10th, 12th resultsWhat does ID-10-T mean? ID-10-T Definition. Meaning of ID-10-T. OnlineSlangDictionary.comId10t Form - Fill and Sign Printable Template Online

It's probably easier to tell you where the +10T does NOT go. Not tothe Digital Control board, VCO board, Translator board, Power Supplyboard, AUX-7 (unless you are using Fixed ctystal controlled transmit),DR-7, or PA module.

The T/R switching transistors are the three-legged fuses on the TR-7.They will pop from even an instantaneous short to ground of the T or Rline. But you could also have dirty/oxidized Molex connectors. Tryre-seating the TX Exciter board first.

73

-Jim

NU0C

On Sun, 25 Feb 2018 14:06:28 +0000 (UTC), Ray Collinsraycollins39@...[DrakeRadio] wrote:

>Looks like the 10T is acting up. In transmit less than 1.5 voltson the ALC I.C.Assuming a bypass capacitor may have taken out transistorsin the transmit exciter board. Or something is pulling the voltage down.What is the 10T bus attached to? Exciter board and the ALC board and whatelse? Thought I'd change all the 10T caps.

>73's

>Ray VE3BDK

--

“There’s something out of place – let’s go and poke it with astick..â€� – The Doctor, "Amy’s Choice"

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Yes, I thought you already knew that. :) You can easily measure both 10T and 10R on the bottom of the parent board. You should be able to test the transistors on the TX Exciter board with an ohmmeter without needing to pull them. The relay is energized by 10T via Q1901 onthe Low Pass Filter module. If you are hearing the relay pull then you must have enouigh on the 10T line to fire the Q1901. Measuring on the parent board the T and R voltages should go to near 10V when active and near 0 when not.

73

-Jim
NU0C

On Mon, 26 Feb 2018 14:47:02 +0000 (UTC), Ray Collins raycollins39@... [DrakeRadio] wrote:

Thanks Jim, I'm assuming the 10t is generated in the Transmitter exciter card? The radio has receive and the relay clicks over. I've changed all the caps on the exciter card, not looking forward to pulling the transistors. The boards been in and out a few times and deoxit applied.

73
Ray VE3BDK

--
“There’s something out of place – let’s go and poke it with a stick.” – The Doctor, "Amy’s Choice"

Jim you would be surprised how much I don't know. ;-)) ÂI read the 10t on the parent board and it appears ok throughout the unit including the ALC board. Tested the mic, it's putting out something. I have a wattmeter and modulation meter on the RF out with a dummy load it shows I'm putting out 5 watts RMS. At a loud level form my voice. I think I can hear the ALC on receive, in transmit the green LED is not working.

73

OK, the service manual is your best friend. The "how sutff works" descriptions
do a very good job of explaining just that. The block diagram near the front
will show you how the signals flow. If your RX seems to be working to spec that
means that most of the RF chain is probably OK. That pretty much leaves the PA
brick and TX Exciter board, but don't overlook the TR relay. Do you have a
proper power cable? If you are using a PS-7 you should be good, but if not make
sure that BOTH positive power pins are connected to +13V. One of them supplies
power to the PA brick and the other to everything else.

ALC control is derived from the forward and reverse power sensors on the Low
Pass FiIter module. ALC is threshold based and will do nothng until power
output reaches the threshold and the green light comes on. Check the RF levels
around the PA brick. If you remove the four screws securing it to the right
side panel it can be pulled out of the radio far enough for service without
disconnecting wires.

73

-Jim
NU0C

On Tue, 27 Feb 2018 20:31:27 +0000 (UTC), Ray Collins raycollins39@...
[DrakeRadio] wrote:

Jim you would be surprised how much I don't know. ;-)) -I read the 10t on the parent board and it appears ok throughout the unit including the ALC board. Tested the mic, it's putting out something. I have a wattmeter and modulation meter on the RF out with a dummy load it shows I'm putting out 5 watts RMS. At a loud level form my voice. I think I can hear the ALC on receive, in transmit the green LED is not working.

73
Ray VE3BDK

--
“There’s something out of place – let’s go and poke it with a stick.” – The Doctor, "Amy’s Choice"

Went through with a scope, signal appears to be ok right up to the out of pre-driver board. I'm assuming the power amp is wonky. I have a parts unit that has a version 2 pre-driver, condition unknown. The one I'm fixing has a version 1 pre driver. I'm also assuming version 2 is the best choice? Also I tried to get the power amp card off once before, it was stuck and rather than use a hammer and a screwdriver I left it alone.;-) ÂHowever while I'm in here I should change the caps, is there a screw I'm missing, all the transistors appear to be bolted to the heat sink. I just realized the power transistors are also bolted to the heat sink, so that may have been what was hanging me up. i thought I would just swap the complete pre and power amps and go from there.

Thanks againÂ

Ray,

Yes, version 2 is the better choice. Although it has its quirks as well. The
best info is in the DrakemodV6 document and in an article on the WB4HFN web
site on restoring the TR-7 to full output. The driver transistors on the PA
board seem to be a weak point. Carefully check the base voltage with a
voltmeter; it should be 0v in RX and around 0.6v in TX with no RF drive.

73

-Jim
NU0C

On Sat, 3 Mar 2018 23:07:06 +0000 (UTC), Ray Collins raycollins39@...
[DrakeRadio] wrote:

Went through with a scope, signal appears to be ok right up to the out of pre-driver board. I'm assuming the power amp is wonky. I have a parts unit that has a version 2 pre-driver, condition unknown. The one I'm fixing has a version 1 pre driver. I'm also assuming version 2 is the best choice? Also I tried to get the power amp card off once before, it was stuck and rather than use a hammer and a screwdriver I left it alone.;-) -However while I'm in here I should change the caps, is there a screw I'm missing, all the transistors appear to be bolted to the heat sink. I just realized the power transistors are also bolted to the heat sink, so that may have been what was hanging me up. i thought I would just swap the complete pre and power amps and go from there.
Thanks again-
Ray VE3BDK

Sent from Yahoo Mail for iPad

On Tuesday, February 27, 2018, 8:47 PM, 'Jim Shorney' jshorney@... [DrakeRadio] <DrakeRadio@...> wrote:

OK, the service manual is your best friend. The "how sutff works" descriptions
do a very good job of explaining just that. The block diagram near the front
will show you how the signals flow. If your RX seems to be working to spec that
means that most of the RF chain is probably OK. That pretty much leaves the PA
brick and TX Exciter board, but don't overlook the TR relay. Do you have a
proper power cable? If you are using a PS-7 you should be good, but if not make
sure that BOTH positive power pins are connected to +13V. One of them supplies
power to the PA brick and the other to everything else.

ALC control is derived from the forward and reverse power sensors on the Low
Pass FiIter module. ALC is threshold based and will do nothng until power
output reaches the threshold and the green light comes on. Check the RF levels
around the PA brick. If you remove the four screws securing it to the right
side panel it can be pulled out of the radio far enough for service without
disconnecting wires.

73

-Jim
NU0C

On Tue, 27 Feb 2018 20:31:27 +0000 (UTC), Ray Collins raycollins39@...
[DrakeRadio] wrote:

Jim you would be surprised how much I don't know. ;-)) --I read the 10t on the parent board and it appears ok throughout the unit including the ALC board. Tested the mic, it's putting out something. I have a wattmeter and modulation meter on the RF out with a dummy load it shows I'm putting out 5 watts RMS. At a loud level form my voice. I think I can hear the ALC on receive, in transmit the green LED is not working.

73
Ray VE3BDK

--
G€œThereG€™s something out of place G€“ letG€™s go and poke it with a stick..G€ G€“ The Doctor, "AmyG€™s Choice"

------------------------------------

------------------------------------

------------------------------------

Yahoo Groups Links

--
The universe we're in will reach absolute zero in three hours. Safe is relative. - Idris, "The Doctor's Wife"

Jim,Â

There's a fiber washer between the pa and the heat sink, it had disappeared on re assembly. Is it a spacer? Or does it keep the traces away from ground?

My luck I will have to pull it apart all over again. Not that I had anything else to do.;-))

73

Best way to find small parts like that......from Garey Barrell,K4OAH (SK).

Take an old nylon stocking or panty hose and cut a piece out of it to tie over the end of your vacuum hose, then start vacuuming!

73

Peter
VE7PS

On 3/6/2018 6:17 AM, Ray Collins raycollins39@... [DrakeRadio] wrote:

Jim,Â

There's a fiber washer between the pa and the heat sink, it had disappeared on re assembly. Is it a spacer? Or does it keep the traces away from ground?

My luck I will have to pull it apart all over again. Not that I had anything else to do.;-))

73

Ray

Sent from Yahoo Mail for iPad

On Saturday, March 3, 2018, 9:07 PM, 'Jim Shorney' jshorney@... [DrakeRadio] wrote:

Ray,

Yes, version 2 is the better choice. Although it has its quirks as well. The
best info is in the DrakemodV6 document and in an article on the WB4HFN web
site on restoring the TR-7 to full output. The driver transistors on the PA
board seem to be a weak point. Carefully check the base voltage with a
voltmeter; it should be 0v in RX and around 0.6v in TX with no RF drive.

73

-Jim
NU0C

On Sat, 3 Mar 2018 23:07:06 +0000 (UTC), Ray Collins raycollins39@...
[DrakeRadio] wrote:

>Went through with a scope, signal appears to be ok right up to the out of pre-driver board. I'm assuming the power amp is wonky. I have a parts unit that has a version 2 pre-driver, condition unknown. The one I'm fixing has a version 1 pre driver. I'm also assuming version 2 is the best choice? Also I tried to get the power amp card off once before, it was stuck and rather than use a hammer and a screwdriver I left it alone.;-) -ÂHowever while I'm in here I should change the caps, is there a screw I'm missing, all the transistors appear to be bolted to the heat sink. I just realized the power transistors are also bolted to the heat sink, so that may have been what was hanging me up. i thought I would just swap the complete pre and power amps and go from there.
>Thanks again-Â
>Ray VE3BDK
>
>
>Sent from Yahoo Mail for iPad
>
>
>On Tuesday, February 27, 2018, 8:47 PM, 'Jim Shorney' jshorney@... [DrakeRadio] <DrakeRadio@...> wrote:
>
>
>OK, the service manual is your best friend. The "how sutff works" descriptions
>do a very good job of explaining just that. The block diagram near the front
>will show you how the signals flow. If your RX seems to be working to spec that
>means that most of the RF chain is probably OK. That pretty much leaves the PA
>brick and TX Exciter board, but don't overlook the TR relay. Do you have a
>proper power cable? If you are using a PS-7 you should be good, but if not make
>sure that BOTH positive power pins are connected to +13V. One of them supplies
>power to the PA brick and the other to everything else.
>
>ALC control is derived from the forward and reverse power sensors on the Low
>Pass FiIter module. ALC is threshold based and will do nothng until power
>output reaches the threshold and the green light comes on. Check the RF levels
>around the PA brick. If you remove the four screws securing it to the right
>side panel it can be pulled out of the radio far enough for service without
>disconnecting wires.
>
>73
>
>-Jim
>NU0C
>
>On Tue, 27 Feb 2018 20:31:27 +0000 (UTC), Ray Collins raycollins39@...
>[DrakeRadio] wrote:
>
>>Jim you would be surprised how much I don't know. ;-)) --ÂI read the 10t on the parent board and it appears ok throughout the unit including the ALC board.. Tested the mic, it's putting out something. I have a wattmeter and modulation meter on the RF out with a dummy load it shows I'm putting out 5 watts RMS. At a loud level form my voice. I think I can hear the ALC on receive, in transmit the green LED is not working.
>>
>>73
>>Ray VE3BDK
>
>--
>G€œThereG€™s something out of place G€“ letG€™s go and poke it with a stick..G€ G€“ The Doctor, "AmyG€™s Choice"
>
>
>
>
>------------------------------------
>
>------------------------------------
>
>
>------------------------------------
>
>Yahoo Groups Links
>
>
>
>
>
>

--
The universe we're in will reach absolute zero in three hours. Safe is relative. - Idris, "The Doctor's Wife"

------------------------------------

------------------------------------

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I don't recall seeing a fiber washer when I had mine apart. Internet photos
have not been forthcoming about the presence of one. I guess you will have to
look for a likely spot.

73

-Jim
NU0C

On Tue, 6 Mar 2018 14:17:47 +0000 (UTC), Ray Collins raycollins39@...
[DrakeRadio] wrote:

blockquote, div.yahoo_quoted { margin-left: 0 !important; border-left:1px #715FFA solid !important; padding-left:1ex !important; background-color:white !important; } Jim,-
There's a fiber washer between the pa and the heat sink, it had disappeared on re assembly. Is it a spacer? Or does it keep the traces away from ground?My luck I will have to pull it apart all over again. Not that I had anything else to do.;-))
73
Ray

Sent from Yahoo Mail for iPad

On Saturday, March 3, 2018, 9:07 PM, 'Jim Shorney' jshorney@... [DrakeRadio] <DrakeRadio@...> wrote:

Ray,

Yes, version 2 is the better choice. Although it has its quirks as well. The
best info is in the DrakemodV6 document and in an article on the WB4HFN web
site on restoring the TR-7 to full output. The driver transistors on the PA
board seem to be a weak point. Carefully check the base voltage with a
voltmeter; it should be 0v in RX and around 0.6v in TX with no RF drive.

73

-Jim
NU0C

On Sat, 3 Mar 2018 23:07:06 +0000 (UTC), Ray Collins raycollins39@...
[DrakeRadio] wrote:

Went through with a scope, signal appears to be ok right up to the out of pre-driver board. I'm assuming the power amp is wonky. I have a parts unit that has a version 2 pre-driver, condition unknown. The one I'm fixing has a version 1 pre driver. I'm also assuming version 2 is the best choice? Also I tried to get the power amp card off once before, it was stuck and rather than use a hammer and a screwdriver I left it alone.;-) --However while I'm in here I should change the caps, is there a screw I'm missing, all the transistors appear to be bolted to the heat sink. I just realized the power transistors are also bolted to the heat sink, so that may have been what was hanging me up. i thought I would just swap the complete pre and power amps and go from there.
Thanks again--
Ray VE3BDK

Sent from Yahoo Mail for iPad

On Tuesday, February 27, 2018, 8:47 PM, 'Jim Shorney' jshorney@... [DrakeRadio] <DrakeRadio@...> wrote:

OK, the service manual is your best friend. The "how sutff works" descriptions
do a very good job of explaining just that. The block diagram near the front
will show you how the signals flow. If your RX seems to be working to spec that
means that most of the RF chain is probably OK. That pretty much leaves the PA
brick and TX Exciter board, but don't overlook the TR relay. Do you have a
proper power cable? If you are using a PS-7 you should be good, but if not make
sure that BOTH positive power pins are connected to +13V. One of them supplies
power to the PA brick and the other to everything else.

ALC control is derived from the forward and reverse power sensors on the Low
Pass FiIter module. ALC is threshold based and will do nothng until power
output reaches the threshold and the green light comes on. Check the RF levels
around the PA brick. If you remove the four screws securing it to the right
side panel it can be pulled out of the radio far enough for service without
disconnecting wires.

73

-Jim
NU0C

On Tue, 27 Feb 2018 20:31:27 +0000 (UTC), Ray Collins raycollins39@...
[DrakeRadio] wrote:

Jim you would be surprised how much I don't know. ;-)) ---I read the 10t on the parent board and it appears ok throughout the unit including the ALC board. Tested the mic, it's putting out something. I have a wattmeter and modulation meter on the RF out with a dummy load it shows I'm putting out 5 watts RMS. At a loud level form my voice. I think I can hear the ALC on receive, in transmit the green LED is not working.

73
Ray VE3BDK

--
GG‚¬+“ThereGG‚¬G„¢s something out of place GG‚¬G€œ letGG‚¬G„¢s go and poke it with a stick..GG‚¬n++ GG‚¬G€œ The Doctor, "AmyGG‚¬G„¢s Choice"

------------------------------------

------------------------------------

------------------------------------

Yahoo Groups Links

--
The universe we're in will reach absolute zero in three hours. Safe is relative. - Idris, "The Doctor's Wife"

------------------------------------

------------------------------------

------------------------------------

Yahoo Groups Links

--
“There’s something out of place – let’s go and poke it with a stick.” – The Doctor, "Amy’s Choice"