Kraco 2555 FM Modifications

Locate the wire connection marked as "1" on the channel selector PCB, remove the wire from it and connect it to the connection marked as "3" on the same board.

 

What it does:

When changing modes between LSB, AM, USB and FM the mode switch disables the channel selector and switches in a diode bank when in the SSB modes, this mode ensures that the channel selector is not disabled and also disconnects the diode bank to enable SSB on all channels !

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Need more channels ?

It is also possible to swap the channel selector to a 40 channel selector as used in many other Cybernet chassis radios, you need a selector that produces a code range of 255-211, get one from a junked radio and bolt it in, should work like a charm, the only tricky bit will be connecting it to the existing channel display, it may take a little bit of thought but it should not be too much of a problem.

 

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The Kraco 2555 comes in two versions the 2555 and the 2555FM, this mod is only confirmed in the FM version, the radios are 24 channel Swedish radios, that have AM (and FM for the FM version) coverage on all channels and SSB only allowed on channel 24.

The 2555 FM uses the PTBM058AOX PCB and the PLL02A, with a code range of 255-226.

 

Thanks to Juha H. for making me aware that these radios even existed and for wanting me to find a way of modifying them, he also sent me the circuit diagrams and digital photos which helped a lot !