Metalwork - Lathe and Mill topics

Re: [Amateur-repairs] Old test eqpt? Chuck it? Refurbish it?

Very funny Jim :)

Alan

AK6MF

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Re: [Amateur-repairs] Old test eqpt? Chuck it? Refurbish it?

I am reminded of this old joke:

https://www.adamsmith.org/blog/miscellaneous/joke-of-the-day-4

On Tue, 01 Jul 2025 18:02:33 -0700
"Alan Majeski via groups.io" <arcadiaresearchgroup=gmail.com@groups.io> wrote:

> I find it interesting that there are still opinions as to what field an engineer should work in or not.
> Engineering is Engineering period.
> --
> Alan
> AK6M

--

73

-Jim
NU0C

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Re: [Amateur-repairs] Old test eqpt? Chuck it? Refurbish it?

I find it interesting that there are still opinions as to what field an engineer should work in or not.

Engineering is Engineering period.

Alan

AK6M

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Re: [Amateur-repairs] Old test eqpt? Chuck it? Refurbish it?

An electrical engineer designing to a price point might use the moving vane method. :D

On Tue, 01 Jul 2025 07:54:53 -0700
"Gary WB6OGD via groups.io" <winbladgary=gmail.com@groups.io> wrote:

> Sounds like a solution a Mechanical Engineer would come up with! Same kind of gadget is in my HP 8640B.
>
> An Electrical Engineer would add a varactor diode (or just any diode) and a potentiometer.

--

73

-Jim
NU0C

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Re: [Amateur-repairs] Old test eqpt? Chuck it? Refurbish it?

On Mon, Jun 30, 2025 at 06:34 PM, Jim Shorney wrote:

grounded metal vane on a rotating shaft

Sounds like a solution a Mechanical Engineer would come up with! Same kind of gadget is in my HP 8640B.

An Electrical Engineer would add a varactor diode (or just any diode) and a potentiometer. Also, that would give

you the option to easily add a "huff and puff" type frequency stabilizer. The old Eico would get actually useful.

73,

Gary

WB6OGD

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Re: [Amateur-repairs] Old test eqpt? Chuck it? Refurbish it?

Hi all,

The real Achilles heel of those analyzers is the flyback transformer. Long ago I had spare kits for them and, trust me, they sold like hot cakes!. Now it is just unobtanium. Another failure points are the OM-345, OM-350 and OM-360/370 amplifiers. But for those there are still some replacement assemblies sold online. I sold also the original ones for a long time and still have some of the models. When they fail, the error codes come in groups, sometimes all and every one.

All in all, I still have a 2955B and is a great instrument, even if the ones I use daily are the the R&S CMTs

73 Jose EB5AGV

El 01/07/2025 a las 9:18, jahman via groups.io escribió:

Well, you're in luck!

Marconi 2955 Communication Service Monitor
$1,990 - https://www.ebay.com/itm/284689545136

$1,950 - https://www.ebay.com/itm/356941529543

$1,750 - https://www.ebay.com/itm/356583617089

$1,523 - https://www.ebay.com/itm/286439999912

$1,340 - https://www.ebay.com/itm/386832700583

73 de Andrew/N5ASE

-0-

On Tue, Jul 1, 2025 at 2:56 AM maxwelloau via groups.io <maxwelloau=gmail.com@groups.io> wrote:

At an Amateur convention recently I picked up two Marconi 2955 units that had been stored in farmer brown's shed for years.

1) All self test failed. Required 4x 4k7 resistors + 2x 220uf 25V capacitors. Unit is in calibration when compared to a 2024 NATA calibrated 2955R and Agilent E4421B signal generator.

2) Full of millipede carcases. No corrosion except small section on rear panel, was fully operational (some scope waveform trigger problems). Old FW was updated but had to include the CAL chip all from another unit. Scope problem was edge connector cleaning. So some calibration was required and manually its a painful process but as my time is retired and worth Zero, its a labour of love.

A testament to the good design Marconi, their designers and the reliability of normal components like R, C, IC and relays. I marvel at the green CRT quality and both 100% usable after 30+ years.

End result is two units destined for the metal scrap bin are now usable and in fact more than very good. Sought after for anyone testing RF and radio equipment.

With the good info from groups.io and using the technician brain you cant beat repairable in my books.

maxwelloau

--   73 EB5AGV - JOSE V. GAVILA - La Canyada - Valencia (SPAIN)     http://agvradio.com  AGVradio     http://jvgavila.com  Personal WEB

Re: [Amateur-repairs] Old test eqpt? Chuck it? Refurbish it?

Well, you're in luck!

Marconi 2955 Communication Service Monitor

$1,990 - https://www.ebay.com/itm/284689545136

$1,950 - https://www.ebay.com/itm/356941529543

$1,750 - https://www.ebay.com/itm/356583617089

$1,523 - https://www.ebay.com/itm/286439999912

$1,340 - https://www.ebay.com/itm/386832700583

73 de Andrew/N5ASE

-0-

On Tue, Jul 1, 2025 at 2:56 AM maxwelloau via groups.io <maxwelloau=gmail.com@groups.io> wrote:

At an Amateur convention recently I picked up two Marconi 2955 units that had been stored in farmer brown's shed for years.

1) All self test failed. Required 4x 4k7 resistors + 2x 220uf 25V capacitors. Unit is in calibration when compared to a 2024 NATA calibrated 2955R and Agilent E4421B signal generator.

2) Full of millipede carcases. No corrosion except small section on rear panel, was fully operational (some scope waveform trigger problems). Old FW was updated but had to include the CAL chip all from another unit. Scope problem was edge connector cleaning. So some calibration was required and manually its a painful process but as my time is retired and worth Zero, its a labour of love.

A testament to the good design Marconi, their designers and the reliability of normal components like R, C, IC and relays. I marvel at the green CRT quality and both 100% usable after 30+ years.

End result is two units destined for the metal scrap bin are now usable and in fact more than very good. Sought after for anyone testing RF and radio equipment.

With the good info from groups.io and using the technician brain you cant beat repairable in my books.

maxwelloau

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Tuesday, 1 July 2025