pres 2510

[warhorse]

Hi a mk1 2510. standard 10.7 filter. cpu-ok replaced the cpu for the current type 12**etc this is not the problem all voltages ok 1to64. freq readout oscillates like a margin ruler on the end of a table as {example}. freq readout is locked out if you twist the freq selector really fast it kind of hops 28-29 the problem lies on this cpu board. I inter changed with the export Lincoln cpu board from a donor working Lincoln, just to see if the main board was the problem worked kind of ok without retuning so this eliminates all the panel buttons etc, no dried out caps or shorted ones.the voltage regs are ok as well the bottom of the board I,e,the foil side has the cylinder type resistors & inductors. other than this all frequency & voltage checks seam ok. I have posted this before so any fresh ideas share them I do have a donor 2510 but its the updated version so this may hold some information ok they are the same except on the cpu at the front left right the extra chip like in a 2600. for tones..i know its hard to ex plane & its easier when a radio is on a bench so i dont expect any mega replies but thanks for your time if you ponder on this.

 

[Rogerbird1]

Questions

I know you have stated that you checked all the voltages on the CPU, But you also state that it has been replaced.. I would check the traces on the top side under the CPU, for breaks or opens. I would check the pins to their associated components on the top and botton of the PCB, for continuity.

Is the new Micro soldered inplace or in a socket?

Does it xmit? if so what freq is it xmitting on?

Can you measure the Freq of the Resonator?

Check Pin 48 to change state with the 'F Lock' button in or out.
Should go from 5V to Ground (when pushed in).

DO the Up/Dn buttons work on the Mic or Front panel?

just some places to start..

Roger