Okay they resistors measure as follows:

Both liftet from PCB

R41=837 OHMS

R89=557 OHMS

So not horrible out of tolerances I guess.

On Mon, Mar 4, 2024 at 11:43?PM Steve Wedge, W1ES/4 via <w1es=[email protected]> wrote:

Those figures don't indicate a problem. Ideally, TP2, with the preselector detuned, should read -1.35V Your reading isn't terrible. So now we need to see why you're getting S5 with no signal. On the schematic, R41 and R89, in the meter bridge circuit, should be checked.

Steve Wedge, W1ES/4

Time flies like an arrow. Fruit flies like a banana.

Sent with secure email.

On Monday, March 4th, 2024 at 3:53 PM, Michael Jensen <kavigal@...> wrote:

@Steve Tonight's numbers :).

Cold and detuned TP2=-1.335v
30 mins TP2=-1.267v
60 mins TP2=-1.259v

I get your point about " The important part here is if the voltage at TP2 with respect to time."

Now what is the verdict? Too much voltage drop? What do you think?

Thanks, Michael.

On Sun, Mar 3, 2024 at 11:49?PM Steve Wedge, W1ES/4 via <w1es=[email protected]> wrote:

Resistance is the most important here.

We now need to measure the TP2 voltage from startup to a point long after warmup. If this value drifts towards 0V then there is a chance that you have a gassy tube.

The important part here is if the voltage at TP2 with respect to time.

Steve Wedge, W1ES/4

Time flies like an arrow. Fruit flies like a banana.

Sent with secure email.

On Sunday, March 3rd, 2024 at 12:50 PM, Michael Jensen <kavigal@...> wrote:

HI again!

Tak for linked Glenn, kunne godt minde lidt om mit problem :).

Okay enough "Danglish" ..

@Steve, Thanks for taking your time to reply!

Detuned and with AVC ON, TP2 voltage is-1.26, right now, I did an adjustment cold, so seems to have dropped ever so slightly after proper warm up.

RF GAIN Pot measures ~12Ohms(seem to be some capacitance) with wires attached, so guess that is quite okay.

Thanks, Michael-oz8abr

On Sun, Mar 3, 2024 at 2:11?PM Steve Wedge, W1ES/4 via <w1es=[email protected]> wrote:

Michael, what is the voltage at TP2? There are other resistors in the bridge circuit and I have seen them go out of tolerance.

What is the resistance reading across the RF GAIN pot?

73,

Steve Wedge, W1ES/4

Time flies like an arrow. Fruit flies like a banana.

Sent from for iOS

On Sun, Mar 3, 2024 at 07:09, Glenn, OZ1HFT <glenn.mh.dk@...> wrote:

Hi Michael

See this thread:

/g/DRAKE-RADIO/topic/r_4b_agc_issues_part_trois/103544827

--
best regards,

Glenn, OZ1HFT

That S meter is so close to useless that it simply does not matter where it rests at zero signal. It simply tells you, “This guy is loud” and “That guy is not loud”.

Gary

W0DVN

> On Mar 4, 2024, at 9:19?PM, Lyndon VE7TFX <lyndon@...> wrote:
>
> Michael Smith via groups.io writes:
>
>> In pre-alignment stage, I have a TR-4C with the S-meter indicating 1.5, wit=
>> h power off and chassis in the normal horizontal position. =C2=A0Is mechani=
>> cally zeroing the S-meter possible, and it is necessary? =C2=A0I=E2=80=99ve=
>> applied a little rotational torque to the chassis to verify the S-meter ne=
>> edle is free to move.
>
> Static buildup? Try rubbing the meter face with a "no cling"
> dryer sheet.
>
> --lyndon
>
>
>
>
>

On Mar 5, 2024, at 1:19?AM, Jim Shorney <jimNU0C@...> wrote:

?
You can measure the +24V from the bottom side of the radio at the pins of the PS board.

However, if the radio is operating normally from an RF standpoint, i.e., the PLL is locked and stable in the ham band that you expect it is a pretty safe bet that the +24 is OK.

My question was about SIMPLIFYING the process to narrow it down between a PLL issue and a problem strictly with the frequency counter section.

73

-Jim
NU0C

On Tue, 5 Mar 2024 01:05:01 -0500
"Adam W4AJF" <adamf@...> wrote:

Hi Jim, thanks for chiming in. Forgive my ignorance, I am not looking at the radio right now, I assume the regulator is 3 pin, which leads do I test for the 24VDC or no 24VDC? Thanks, Adam

On Mar 5, 2024, at 12:55?AM, BOB DOSTALL via groups.io <bdostall@...> wrote:

?
No need to overthink it for a change. Check the output of that 24v regulator. 0v is no good. I know that there a few experts on here. But the radio is pretty simple.

On Tuesday, March 5, 2024 at 12:37:29 AM EST, Jim Shorney <jimnu0c@...> wrote:

Is the radio operating normally otherwise? In the correct band and stable? That will help localize the problem area.

73

-Jim
NU0C

On Mon, 4 Mar 2024 23:07:19 -0500
"Adam W4AJF" <adamf@...> wrote:

Thanks Bob, I am going to resolder the pins first, if no luck I’ll replace that part. Thanks! Adam W4AJF



On Mar 4, 2024, at 7:49?PM, BOB DOSTALL via groups.io <bdostall@...> wrote:

?
I had that issue recently on a radio in the shop for repair. It was the 24v regulator U2103. M78L24c
Bob KF8IY

On Monday, March 4, 2024 at 03:14:08 PM EST, Adam W4AJF <adamf@...> wrote:

Hi all, I have an issue with the display board in one of my Drake
TR-7's and it's the board for sure because I installed the problem
board in another TR-7 and it has the EXACT same issue: On the TR-7
with the issue it was fine and not used for a while, turned it on and
now the display shows 51.950 on all bands. The VFO will move it up and
down but of course it will still be in that range on all bands but it
does receive and transmit. I see this issue has been discussed on this
web site but I don't see any answers?

Any help appreciated, I am hoping someone has figured out how to fix
this Specific issue.

Adam Farber W4AJF
Cooper City, FL

--

73

-Jim
NU0C

--

73

-Jim
NU0C

On Mar 5, 2024, at 12:55?AM, BOB DOSTALL via groups.io <bdostall@...> wrote:

?

No need to overthink it for a change. Check the output of that 24v regulator. 0v is no good. I know that there a few experts on here. But the radio is pretty simple.

On Tuesday, March 5, 2024 at 12:37:29 AM EST, Jim Shorney <jimnu0c@...> wrote:

Is the radio operating normally otherwise? In the correct band and stable? That will help localize the problem area.

73

-Jim
NU0C

On Mon, 4 Mar 2024 23:07:19 -0500
"Adam W4AJF" <adamf@...> wrote:

> Thanks Bob, I am going to resolder the pins first, if no luck I’ll replace that part. Thanks! Adam W4AJF?
>
>
>
> On Mar 4, 2024, at 7:49?PM, BOB DOSTALL via groups.io <bdostall@...> wrote:
> >
> > ?
> > I had that issue recently on a radio in the shop for repair. It was the 24v regulator U2103. M78L24c
> > Bob KF8IY
> >
> > On Monday, March 4, 2024 at 03:14:08 PM EST, Adam W4AJF <adamf@...> wrote:
> >
> >
> >
> > > Hi all, I have an issue with the display board in one of my Drake
> > > TR-7's and it's the board for sure because I installed the problem
> > > board in another TR-7 and it has the EXACT same issue: On the TR-7
> > > with the issue it was fine and not used for a while, turned it on and
> > > now the display shows 51.950 on all bands. The VFO will move it up and
> > > down but of course it will still be in that range on all bands but it
> > > does receive and transmit. I see this issue has been discussed on this
> > > web site but I don't see any answers?
> > Any help appreciated, I am hoping someone has figured out how to fix
> > this Specific issue.
> > > Adam Farber W4AJF
> > > Cooper City, FL
> > >
> >
> >
> >
> >
> >
> >
> >
>



--

73

-Jim
NU0C

On Mar 4, 2024, at 7:49?PM, BOB DOSTALL via groups.io <bdostall@...> wrote:

?

I had that issue recently on a radio in the shop for repair. It was the 24v regulator U2103. M78L24c

Bob KF8IY

On Monday, March 4, 2024 at 03:14:08 PM EST, Adam W4AJF <adamf@...> wrote:

> Hi all, I have an issue with the display board in one of my Drake

> TR-7's and it's the board for sure because I installed the problem

> board in another TR-7 and it has the EXACT same issue: On the TR-7

> with the issue it was fine and not used for a while, turned it on and

> now the display shows 51.950 on all bands. The VFO will move it up and

> down but of course it will still be in that range on all bands but it

> does receive and transmit. I see this issue has been discussed on this

> web site but I don't see any answers?

Any help appreciated, I am hoping someone has figured out how to fix

this Specific issue.

> Adam Farber W4AJF

> Cooper City, FL

>

On Mar 4, 2024, at 9:29?PM, Lyndon VE7TFX <lyndon@...> wrote:

?Rick W4XA writes:

I am re-building the power supply for my Hallicrafters HT-45 Loudenboomer (=
single 3-400) using a plate transformer out of a Drake L-4PS. =C2=A0 =C2=A0=
It'll get the same SSR and won't be wired for switchable plate voltage.

Oh do tell! I have a Loudenboomer here pining to meet a suitable
PSU. I had thought about trying to replicate the original PSU (I
even have the 866s!), but re-purposing an existing HV supply is
probably the more relistic solution. I would be very curious to
see what you come up with.

--lyndon

On Mar 4, 2024, at 9:19?PM, Lyndon VE7TFX <lyndon@...> wrote:

Michael Smith via groups.io writes:

In pre-alignment stage, I have a TR-4C with the S-meter indicating 1.5, wit=
h power off and chassis in the normal horizontal position. =C2=A0Is mechani=
cally zeroing the S-meter possible, and it is necessary? =C2=A0I=E2=80=99ve=
applied a little rotational torque to the chassis to verify the S-meter ne=
edle is free to move.

Static buildup? Try rubbing the meter face with a "no cling"
dryer sheet.

--lyndon