R-2600CHS Generate mode Spurs

[Tech31yrs]

I just recently acquired a R-2600CHS and as far as I can determine everything in it works the way it is supposed to, with one catch. In Generate mode on AM with no modulation (just carrier) when listening to this on a Ham radio with radio in AM mode at say 14.200 MHz all I hear and see on the S-Meter is the carrier. If I use the wheel and change the frequency to 14.1990 MHz I hear the carrier with spurs every 250hz, at 14.1980 they are spaced at 500hz and at 14.1970 they are 750hz. Is this normal for this unit in AM? I don't hear the spurs on FM Generate. Just wondering if anyone has had this problem and what was involved in fixing it?

I have Vol 1 and 2 of the Service Manuals. The SM completes the internal system calibration for all 4 sections and the unit has the latest Firmware. At this time I have found no "cap crud" or leaking ones but it will get recapped before they start giving me the problems I bought it for, which is to replace 3 Stabilock 4031's that leaking caps have nearly eaten into oblivion.

TIA
Mitch
N4MF

[bh7juo]

No any modulation output in FM mode? I suggest check modelation section......Recapped? First check any wrong in recapped section(caps swap,supply votage,etc....)You have service manual is lucky,I also want it.

[Tech31yrs]

I finally got around to looking at this and it appears I have a problem on the Processor Module. When using the audio generator it will only step every 4th count when setting the output level (eg. .004, .008, .012, .016 it steps) all values between these there is absolutely no change in level. Mine has the "Newer" Processor Board where everything is PLCC and SMD except the Roms and has the 2 cable connectors in the middle of the board. My manual has this boards schematic but only shows the back of the board in the PDF section and doesn't have the drawing page denoting what part ID is what on the board. Does anyone have the part designations drawing for this board?

Mitch
N4MF

[crash]

Hi Mitch,

I have an R2001C that I am recapping.
You may be surprised at how little cap crud you may find,
but still have leaking and bad caps.

My unit has strange black puffy crud in some areas, but not the
typical corrosive damage I have experienced with other equipment.

Some caps show staining of the bottom of the cap from the electrolyte,
with no can swelling, or venting plug bulging in evidence.
I started to replace a few caps, but as I pulled and checked the caps that
looked good, I found them ohmic and the values had drifted, so I am doing
them all.
I am using an ESR circuit with my function generator and scope, and the
ohmic caps are readily identifiable in circuit. The out of tolerance caps
have to be pulled to read.

I wish you luck with your project!
Jeff N8CMQ