26-01-2013, 02:49 PM
I have tried all avenues suggested and I cannot find the service manual or circuit for this EU3. The DAC90 is very similar except for the front end where as you might guess I have a problem. This model has no internal aerial and I need to use my long wire aerial.
If I apply the aerial to the grid (top cap) of first valve, its terrific in signal strength with bags of volume on most of MW band, SW seems to be OK too. Putting the aerial to the aerial socket produces no results at all. Easy! I thought, just trace it out, well the socket is capacitively coupled so I bypassed it --nothing, so out with the meter and I was reading pretty well a dead short from the signal feed to ground.
At this point I lost my presence of mind by continuing to look for a short cct which when I found it light dawned, that I was trying to check an ac. cct with dc methods.
The "short" is of course the tuning coil which is about 0.5 ohm to ground. Not a fault at all. Well due to the set having 3 shortwave and 1 medium waveband there are quite a few coil mounting formers and a scattering of small wax caps most of which the values are not identifiable. They are all fitted into a small area and working in here is difficult and can be destructive, since wires fall of caps and the wiring is very stiff and hard. I think the cct of the Bush AC81 is similar in concept but a much different layout.
Next I will bodge in a coupling cap to feed the a/e socket to the valve grid.
If I can get it all prepared then I will wait for a cct to appear before I have another go
Any comments or ides would be very welcome
Jim
If I apply the aerial to the grid (top cap) of first valve, its terrific in signal strength with bags of volume on most of MW band, SW seems to be OK too. Putting the aerial to the aerial socket produces no results at all. Easy! I thought, just trace it out, well the socket is capacitively coupled so I bypassed it --nothing, so out with the meter and I was reading pretty well a dead short from the signal feed to ground.
At this point I lost my presence of mind by continuing to look for a short cct which when I found it light dawned, that I was trying to check an ac. cct with dc methods.
The "short" is of course the tuning coil which is about 0.5 ohm to ground. Not a fault at all. Well due to the set having 3 shortwave and 1 medium waveband there are quite a few coil mounting formers and a scattering of small wax caps most of which the values are not identifiable. They are all fitted into a small area and working in here is difficult and can be destructive, since wires fall of caps and the wiring is very stiff and hard. I think the cct of the Bush AC81 is similar in concept but a much different layout.
Next I will bodge in a coupling cap to feed the a/e socket to the valve grid.
If I can get it all prepared then I will wait for a cct to appear before I have another go
Any comments or ides would be very welcome
Jim
