[TenTec] corsair 1

Dukes HiFi dukeshifi at comcast.net
Tue Mar 28 22:31:51 EDT 2017

Those may cause a problem, but that problem would have always been present. The thing could never have worked since, no one in their right mind would change the and the radio certainly would never have left Sevierville with that error in place.

The display in that radio is a real counter, as I am sure you know. However, it is only “counting” the VFO. The remaining display counts are preloaded as an offset,  depending upon band. This offset takes into account the BFO frequency (9 MHz nominally) and the crystal HFO ( varies with band). On some bands, it adds the PTO to the offset, on some it subtracts the PTO from the offset. In all cases the display needs information from the band switch to tell it what offset to use and in what direction to do the math.

If the VFO jumper is unplugged, the offset values are as follows:

160, 80 and 40  = -.1.0000
18 and 10 =  91.0000
20, 15, 12 and 10 = 09.0000

These are the Sideband Normal numbers.  Add or subtract 3 KHz for the reverse sideband.

The counter should pass this test regardless of other problems in the radio unless the bandswitch information is wrong or corrupted (by a dirty switch wafer).

If there is NO signal at the VFO input, the display simply displays the offset. However, this is unlikely since you get proper operation on the mentioned bands and the pTO does not care what band you are on, its output is always the same.


> On Mar 28, 2017, at 10:38 AM, ROLAND HOWELL <snowy.howell at btinternet.com> wrote:
> Hi All, some help from you learned gents out there please.I recently found a faulty Corsair 1 in my loft, couldn't remember how long its been there, so I decided to try and resurrect it.sorting through a couple of problems pertaining to the readout of certain bands, it covers 1.8mHz thru' to 29.5mHz.Readout on the following bands is correct:-1.8, 3.5, 7, 21, 24.5, 28 - 29mHzbut on the following bands it is totally wrong:switch on 10mHz, display reads 28mHz-----"-----   14mHz, display reads 96mHz-----"-----   18mHz, display reads 27mHz-----"-----    29.5mHz, display reads 1.5mHzI initially thought the crystals in the osc/mixer had been put in the wrong order, but I have the user manual and the picture of the osc pcb shows most of the crystal numbers so I refitted them in that order.It didn't make any difference to the readout.I injected a signal into the radio of 29.5mHz, turned the selector switch onto that band and tuned the radio to 1.5mHz, there was the signal, so it appears that the radio is on frequency and it is just the readout that is wrong.I opened up the display module and checked the diode component orientation to the picture in the manual, seems ok, however I have a revision A time-base board which is NOT shown in the book. So the question is ( yes I finally got around to asking it hi hi), would the diodes on the display boards cause the erroneous readings either O/C or S/Cthanks for your time and patience in reading thru' this.73, snowy, g0hze     
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