Main problem with 2955 sets is the failure of one or more Philips OM series hybrid amplifiers which are now obsolete and hard to find. When they fail, you can get several problems, as low output power, lack of sensitivity and so on. Please, check my Marconi 2955A page for some info about OM modules location and related failures.
Another Marconi equipment which uses the same modules are the 2022 series generators.
OM modules used on each model are these:
New and Tested OM-345 OM-2045 Replacement module PCB for Marconi 2022, 2955 series and others. It has been developed by John Davis and I distribute them.
Specification is not the same but similar to the OM-345 / OM-2045. It uses a MMIC RF Amplifier (50 Ohm) and two resistors in parallel to give the 12mA bias current and about 13dB in gain.
Dimensions of PCB are 13 x 8 x 1mm . Pin 1 ID is on the copper layer, not the silkscreen ,so it will not rub off.
No modifications are needed, but the unit may require recalibration.
These modules with MMIC RF amplifier are renowned for being very reliable.
A tech note will be included (in digital format) with every order.
Any questions, please ask.
Next picture shows modules fitted on a Marconi 2022C (AB1-2 PCB):
These kits are comprised of a new flyback transformer (with improved specifications), an adaptor PCB to exactly fit old flyback pattern, a couple improved components and detailed instructions (sent by e-mail) to install the kit. These are clones of the Marconi designed kits and have been used successfully in several units.
There are two Kits available, referenced as Kit #1 and Kit #2.
IMPORTANT: These flybacks are of the right type; in the picture you can see that there are similar ones, but with cable output in vertical. They are not physically compatible and need some mechanical work to make them barely fit in a 2955. So be sure to get the correct one, which is plug and play (note that cable color is irrelevant)
|OM-345 / OM-2045 REPLACEMENT MODULE PCB||AVAILABLE|
|Input DUMMY LOAD||OUT OF STOCK|
|OM-345||OUT OF STOCK - see REPLACEMENT PCB|
|OM-350||OUT OF STOCK|
|OM-360L||OUT OF STOCK (see OM-360)|
|OM-2045 (upgraded OM-345)||OUT OF STOCK - see REPLACEMENT PCB|
|OM-2050 (upgraded OM-350)||OUT OF STOCK|
|OM-2060 (upgraded OM-360L)||OUT OF STOCK|
|Flyback Kit #1 (v3)||VERY FEW AVAILABLE|
|Flyback Kit #2||OUT OF STOCK|
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Shipping and handling worldwide by Registered Mail (a track number is provided) is calculated by PayPal shopping cart, depending on total amount. It goes from 7 to 15 EUR
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Hope this helps to fix some unworking 2955s!
You can contact me at email@example.com for more information or questions.