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?Sorry team if u feel this is unrelated, but I have a major desktop issue with web access and until I correct this my Drake related exchanges stop….
So simple; I cannot get and hold a website without the pc rebooting,,,not shutting down, just rebooting. I have trouble shot this for 3weeks believing it to be software but my win10 runs all other apps perfect…. My qth is 4 miles south of Nashua,NH in mass…..it was suggested to take the pc to Geeksquad, but a few rumors have resulted in that they are not as good as they once were, expensive bcz they will change out parts by process of elimination costing bundles like a car shop. So any ideas on a good pc tech?
Tom nu2w.

_._,_._,_

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Mark,

There should be in the group files or photos section a clip of a QST blurb about bypassing the regulators. If it is not there I can probably dig it up.

As for grounding, there is a point at the top right rear corner of the HPF module with a nearby hole in the inner chassis wall that suggests a ground strap that was not included. Grounding this point helps with TX stability so it may help with RX as well. The only other chassis ground point for the HPF is at the opposite corner by the speaker and there are several RF carrying coax cables snaking out through the rig from the HPF. Again, there is a photo available somewhere in the group. Search the messages for "40 meter oscillation". If you can't find it I can dig it up again as well.

73

-Jim
NU0C

On Fri, 29 Mar 2024 03:43:04 -0700
"atlasstuff" <g4fph@...> wrote:

Dieter,
Jim,

Thanks for your replies. So, my repaired radio still has two issues.

(1) Dieter, you were correct in identifying that the source of the 1 kHz spurs on TX output is the DR7 board. Unplugging the connector that feeds it with 12 Volt removes the spurs. Actually, I had noticed previously that, sometimes(!), when I disconnected the antenna from the radio, I could hear 'one-thousand-and-one' very low-level spurs in the receiver when I tuned through the bands. Applying pressure to the metalwork surrounding the HPF would eliminate most of them, so I had just put this down to grounding issues / my not having the case on the radio.

With the 'scope, I measure around 60 mV p-p of 1 kHz on the DR7 end of R9072, the 5-Ohm, 5-Watt resistor. The other end of this resistor is pretty clean, as you would expect, as is the ground wire in the 'P4' connector. Probing U9034, the 5-Volt regulator for the DR7, suggests the 1 kHz is not being generated there. The way Drake treats it's three-terminal regulators, putting them on the end of long leads with no bypass capacitors close to the IC, is crazy though, as you noted, Jim.

Looking at the circuit, there are plenty of references to 1 ms being present around the ICs, with hardly a bypass cap. in place on the board, so I shall have a probe around to try to localise the noise.

I've not changed any of the capacitors on the DR7 board but, after 45 years, some of them may be getting 'tired'.

(2) Likewise, Jim, I have not changed any capacitors on the Transmit Exciter board. The crackling noise could well be indicative of a coupling capacitor that is life-expired. I will either get the extender cards out and have a probe, or just change the likely suspects first to see if that makes a difference.

On the positive side, the TX audio from the TR-7, with the Noble Radio SSB filter and a Shure 444 microphone, sounds great!

Regards,

Mark, G4FPH.

--

73

-Jim
NU0C

Dieter,
Jim,

Thanks for your replies. So, my repaired radio still has two issues.

(1) Dieter, you were correct in identifying that the source of the 1 kHz spurs on TX output is the DR7 board. Unplugging the connector that feeds it with 12 Volt removes the spurs. Actually, I had noticed previously that, sometimes(!), when I disconnected the antenna from the radio, I could hear 'one-thousand-and-one' very low-level spurs in the receiver when I tuned through the bands. Applying pressure to the metalwork surrounding the HPF would eliminate most of them, so I had just put this down to grounding issues / my not having the case on the radio.

With the 'scope, I measure around 60 mV p-p of 1 kHz on the DR7 end of R9072, the 5-Ohm, 5-Watt resistor. The other end of this resistor is pretty clean, as you would expect, as is the ground wire in the 'P4' connector. Probing U9034, the 5-Volt regulator for the DR7, suggests the 1 kHz is not being generated there. The way Drake treats it's three-terminal regulators, putting them on the end of long leads with no bypass capacitors close to the IC, is crazy though, as you noted, Jim.

Looking at the circuit, there are plenty of references to 1 ms being present around the ICs, with hardly a bypass cap. in place on the board, so I shall have a probe around to try to localise the noise.

I've not changed any of the capacitors on the DR7 board but, after 45 years, some of them may be getting 'tired'.

(2) Likewise, Jim, I have not changed any capacitors on the Transmit Exciter board. The crackling noise could well be indicative of a coupling capacitor that is life-expired. I will either get the extender cards out and have a probe, or just change the likely suspects first to see if that makes a difference.

On the positive side, the TX audio from the TR-7, with the Noble Radio SSB filter and a Shure 444 microphone, sounds great!

Regards,

Mark, G4FPH.

I have noticed some low level noise in the TR7 audio when I was working on another issue but did not investigate. It was far enough down to not be of much concern.

Your spurs are likely from the DR7 as Dieter noted. Adding extra filtering is one option. It is worth noting that Drake neglected the small value bypass caps recommended on manufacturer data sheets for the three terminal regulators. I've come to understand over the years that they make recommendations like this for good reasons. You may also consider replacing the electrolytics on both the DR7 and the Transmit Exciter board with modern parts. They are getting old. And do replace C2108 on the power supply board if it is the original part. That is the cap in the radio that is most likely to fail with age and heavy use. You won't be sorry. Be prepared to adjust the +10V and Fixed Passband pots because they will have moved when you touch the PS board. This also may help with your carrier suppression. It is strongly recommended to replace them with 10 turn trimpots.

Resist the temptation to add capacitance to the +10T +10R rails. This will impact your T/R turnaround time.

73

-Jim
NU0C

Your spurs are likely from the DR7 as Dieter noted.

On Thu, 28 Mar 2024 12:37:14 -0700
"atlasstuff" <g4fph@...> wrote:

I think this warrants a new topic, rather than tag it on to my 'repair journey' one.

Making a critical assessment of the transmitter performance of my fixed TR-7 prior to using it on-air: When in LSB mode, the best I can balance the carrier out to is around -55 dB, which is somewhat short of the Drake spec. of -60. Also, along with the (suppressed) carrier, I see two other, single-tone, signals coming out of the transmitter - one at carrier minus (exactly) 1 kHz at -65 dB and another at carrier minus (exactly) 2 kHz at -75 dB. Anyone know whether these are typical / where this 1 kHz 'modulation' comes from? The measurements I am making are with the mic. gain at zero and transmitter into a dummy load, so not getting in through the mic socket.

My second question: Is the mic amp. in the TR-7 particularly noisy? With no microphone plugged in, winding the mic gain up to maximum I get a 'crackly' TX noise floor of around -45 dB flat across the entire SSB filter bandwidth. With the mic gain set to minimum, all I see / hear are the carrier plus two other single-tone signals described above. The crackle sounds somewhat 'interesting' to just be gain-related noise.

Full disclosure: My TR-7 is now sporting a Noble Radio 'NR-FL2.8' 2.8 kHz bandwidth SSB filter in place of the stock Drake 2.3 kHz one, plus a Heathkit Shop power supply board. Perhaps Mike will chime in if he sees this and if there's anything on his board that runs at exactly 1 kHz!

Regards,

Mark, G4FPH.

--

73

-Jim
NU0C

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Hi Mark,

I had a TR7A where noise from the DR7 was audible in the RX. It disappeared when I disconnected the DR7. Additional electrolytics were needed to get rid of this.

So if you disconnect the DR7 (connector near the big resistor on the right side), is your spurious still there?

73, Dieter DL5RDO

I think this warrants a new topic, rather than tag it on to my 'repair journey' one.

Making a critical assessment of the transmitter performance of my fixed TR-7 prior to using it on-air: When in LSB mode, the best I can balance the carrier out to is around -55 dB, which is somewhat short of the Drake spec. of -60. Also, along with the (suppressed) carrier, I see two other, single-tone, signals coming out of the transmitter - one at carrier minus (exactly) 1 kHz at -65 dB and another at carrier minus (exactly) 2 kHz at -75 dB. Anyone know whether these are typical / where this 1 kHz 'modulation' comes from? The measurements I am making are with the mic. gain at zero and transmitter into a dummy load, so not getting in through the mic socket.

My second question: Is the mic amp. in the TR-7 particularly noisy? With no microphone plugged in, winding the mic gain up to maximum I get a 'crackly' TX noise floor of around -45 dB flat across the entire SSB filter bandwidth. With the mic gain set to minimum, all I see / hear are the carrier plus two other single-tone signals described above. The crackle sounds somewhat 'interesting' to just be gain-related noise.

Full disclosure: My TR-7 is now sporting a Noble Radio 'NR-FL2.8' 2.8 kHz bandwidth SSB filter in place of the stock Drake 2.3 kHz one, plus a Heathkit Shop power supply board. Perhaps Mike will chime in if he sees this and if there's anything on his board that runs at exactly 1 kHz!

Regards,

Mark, G4FPH.

Check to see that the set screws on the knob and shaft couplers are tight and not slipping.

--
73 de Mike, W1NR

THAT was the equation. EXISTENCE!... SURVIVAL... must cancel out... programming!

- Ruk -

Recently acquired a L4-B that had not been used in many years. Completed the usual mods in both pieces. When adjusting Plate Control Knob realized variable not always moving. Thinking May be old grease may be binding attempted to use some spray lubricant without much success. Where do I go from here??

Thanks,
--
Donald Pingitore

Hi Steve

Check if C3, C4, C167, crystal socket conductor legs is ok.

Try to disconnect C5 (test C5).

Schematic:

backup:


--

best regards,

Glenn, OZ1HFT

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I’d have to second this comment. Unless it’s been in a fire and then run over by a firetruck, the TR7 is quite repairable. There’s lots of used parts floating around, too.

Mike, wb8vge

Joseph K4JNG writes:

I have stated several times that the $3,500 "sale" never happened. I
fat-fingered a last second bid and then retracted it. I didn't intend to
create a "fiasco". Hope this puts it to rest, once and for all.

Oh, I get it now. So it didn't go for the other sellers max
bid of $3500. Do you recall what it did sell for? I still
can't track that sale down in eBay's sales history. (I have
noticed some inconsistency there lately. Some auctions show
up when I search ebay.com, but are absent from ebay.ca, even
though the seller lists Canadian shipping. Just weird ...)

--lyndon

Folks:

I have stated several times that the $3,500 "sale" never happened. I
fat-fingered a last second bid and then retracted it. I didn't intend to
create a "fiasco". Hope this puts it to rest, once and for all.

Best 73,
joe

joseph n. graif
k4jng

Should work. I was looking to restock my 1N5711s and found a 250pc spool for 25 bucks. I have a lifetime supply now.

73

-Jim
NU0C

On Wed, 27 Mar 2024 12:05:19 -0700
"Bill NZ0T" <nz0tham@...> wrote:

I scored some new Semtech 1N60P Schottky diodes from the USA on Ebay.? Should be here by next week.

I scored some new Semtech 1N60P Schottky diodes from the USA on Ebay.? Should be here by next week.

Why exactly was it declared "dead"? The TR7 is quite repairable. I would go so far as to say it is one of the most repairable transceivers in it's niche and certainly more repairable than most "modern" rigs. If you don't want it I would be happy to take it off your hands. :)

73

-Jim
NU0C

On Wed, 27 Mar 2024 08:48:11 -0700
"Joseph K4JNG" <jgraif1@...> wrote:

Hello all:

My TR7 has been declared all but dead by the individual currently helping me restore my 7-line equipment. Does anyone have one for sale, preferably one that has been restored/brought up to spec? Please advise...

Best 73,
joe - K4JNG