Syncal 30 MF VCO non op - - UK Vintage Radio Repair and Restoration Discussion Forum

hellozero · 4th Mar 2019, 11:55 pm

I working on restoring full operations on an early Syncal 30 - when I select 1X MHz (ie 10 and up) the VCO doesn't want to appear to kick on - the LF and HF VCOs are ok (1-9.999 and 20.000 and up) - logic to turn power on is OK, as is turn on transistor - inductor and caps are ok - all variac/diodes test the same values - wonder what Im missing - all transistors test ok and 34MHz is constant though 1.4MHz is off of course when out of lock sound happened - wonder if we have something up with the BSX38 gone low gain or...anyone had a similar prob -sorting this unit out for a demo is London to celebrate the start of the Transglobe expedition in 1979 in Sept. thanks Laurence G4DMA

ex seismic · 5th Mar 2019, 10:19 am

Try the Yahoo Racal manpack group. Glad to say mine was OK when last used but has had shorted tants in the past.

GMB · 5th Mar 2019, 10:33 am

I have repaired quite a few Syncal-30's including VFO faults so am fairly familiar with the kinds of problems that they get.

All the versions I have worked on have a single VCO controlled by digital logic. You need to check the control voltage of the VCO to see what is going on. The logic ICs do fail in strange ways in my experience so this is one reason for certain ranges not working.

Another common problem with Syncal's is transistors having low gain. It is mainly the simple control logic where this is usually a problem and tends to cause problems like the TX not keying up or the CW mode not working. They clearly had a bad batch of transistors.

ex seismic · 5th Mar 2019, 1:14 pm

Laurence,

I saw the request for help with a Syncal but didn't offer mine. If you are planning QSOs then I would be happy to join in with mine. I'm in Kent so not exactly Dx from London but might be better than nothing. Incidentally at the time of the expedition my wife help train Ginny in voice procedure through the TA.

Gordon
G7KNS

hellozero · 5th Mar 2019, 11:47 pm

Many thanks for all the responses, and Ill go to the racal manpacks if I get stuck - I think its low gain so Im going to swap out the BSX38 when one arrives. I picked up an odd synthd Comcal too and can take parts from that too - all cals test ok as does voltages - The logic appears ok, but again, on advice Ill check the dividers too as suggested. Gordon - we are setting up a "camp" at the RGS Kensington as it was in the Antarctic for Ollie, Charlie and Rans crossing - so tent, skidoos will be in place, together with the syncal30 ill be bringing from Alaska - don't think Ill be active as a static display. Super stuff on your wife training Ginny -she was pretty good on voice procedure, sad loss, too young. The days of sending a Muirfax for 20 mins for one black and white photo back to RAE Farnborough and Portishead remain on HF remain strong. 73 Laurence G4DMA KL7L et al

4th Mar 2019, 11:55 pm	#1
hellozero Diode Join Date: Mar 2019 Location: Anchorage, Alaska, USA. Posts: 3	Syncal 30 MF VCO non op - I working on restoring full operations on an early Syncal 30 - when I select 1X MHz (ie 10 and up) the VCO doesn't want to appear to kick on - the LF and HF VCOs are ok (1-9.999 and 20.000 and up) - logic to turn power on is OK, as is turn on transistor - inductor and caps are ok - all variac/diodes test the same values - wonder what Im missing - all transistors test ok and 34MHz is constant though 1.4MHz is off of course when out of lock sound happened - wonder if we have something up with the BSX38 gone low gain or...anyone had a similar prob -sorting this unit out for a demo is London to celebrate the start of the Transglobe expedition in 1979 in Sept. thanks Laurence G4DMA

5th Mar 2019, 10:19 am	#2
ex seismic Heptode Join Date: Sep 2009 Location: Tonbridge, Kent, UK. Posts: 686	Re: Syncal 30 MF VCO non op - Try the Yahoo Racal manpack group. Glad to say mine was OK when last used but has had shorted tants in the past.

5th Mar 2019, 10:33 am	#3
GMB Dekatron Join Date: Aug 2003 Location: near Reading (and sometimes Torquay) Posts: 3,093	Re: Syncal 30 MF VCO non op - I have repaired quite a few Syncal-30's including VFO faults so am fairly familiar with the kinds of problems that they get. All the versions I have worked on have a single VCO controlled by digital logic. You need to check the control voltage of the VCO to see what is going on. The logic ICs do fail in strange ways in my experience so this is one reason for certain ranges not working. Another common problem with Syncal's is transistors having low gain. It is mainly the simple control logic where this is usually a problem and tends to cause problems like the TX not keying up or the CW mode not working. They clearly had a bad batch of transistors.

5th Mar 2019, 1:14 pm	#4
ex seismic Heptode Join Date: Sep 2009 Location: Tonbridge, Kent, UK. Posts: 686	Re: Syncal 30 MF VCO non op - Laurence, I saw the request for help with a Syncal but didn't offer mine. If you are planning QSOs then I would be happy to join in with mine. I'm in Kent so not exactly Dx from London but might be better than nothing. Incidentally at the time of the expedition my wife help train Ginny in voice procedure through the TA. Gordon G7KNS

5th Mar 2019, 11:47 pm	#5
hellozero Diode Join Date: Mar 2019 Location: Anchorage, Alaska, USA. Posts: 3	Re: Syncal 30 MF VCO non op - Many thanks for all the responses, and Ill go to the racal manpacks if I get stuck - I think its low gain so Im going to swap out the BSX38 when one arrives. I picked up an odd synthd Comcal too and can take parts from that too - all cals test ok as does voltages - The logic appears ok, but again, on advice Ill check the dividers too as suggested. Gordon - we are setting up a "camp" at the RGS Kensington as it was in the Antarctic for Ollie, Charlie and Rans crossing - so tent, skidoos will be in place, together with the syncal30 ill be bringing from Alaska - don't think Ill be active as a static display. Super stuff on your wife training Ginny -she was pretty good on voice procedure, sad loss, too young. The days of sending a Muirfax for 20 mins for one black and white photo back to RAE Farnborough and Portishead remain on HF remain strong. 73 Laurence G4DMA KL7L et al