Serial Number: | N0714 |
Year of Manufacture:  | ? |
Date of Receipt: | ~1996 |
State upon Receipt: | Non-functional. Power supply circuitry a mess. Most paper caps snipped out. |
Repairs:
3/4 mixer subchassis rebuilt.
Stripped down completely, all new RC, except C336A (10pF).
R302 replaced with 75 ohms instead of 47.
C343 replaced with 800 pF instead of 820.
Tested in N0115. Functional. 1.7MHz crystal oscillator tweaked. | |
VFO-1 finished.
All new RC, except 2 mica and 2 tubular ceramic caps. RF input coax replaced with piece of subminax (75 ohm). Band-switching rewired. Three output wires replaced. | |
Work on VFO-2.
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VFO-2 rebuild completed. 10pF mica cap original, other 2 micas replaced. | |
Main chassis work begun. Power supply compartment cleaned out. | |
IF strip rebuild completed. | |
Main chassis rebuild completed.
Previously replaced oversized System switch replaced with another switch. Both replacements are typical break-before-make types rather than the proper make-before-break type used in these receivers. | |
Chassis reassembled. Powered up. Functional. 2nd VFO alignment very good. 1st VFO good alignment at low end, off at high end. | |
1st VFO aligned with frequency counter.
Problem has developed giving high noise level and low sensitivity. Fixed after pulling and reinserting V9. | |
1st VFO aligned with frequency counter.
Restoration completed, except for optional alignment of bandpass filters. | |
Second purchased crystal calibrator rebuilt and installed. Needed instrument alignment but still needed tweaking and tube replacement after instruments to get it to work. | |
Significant arcing on break-before-make System switch observed.
Switch replaced with a proper make-before-break type from unit N0115. This switch was noted to have arc-damaged contacts on the S5.1L pole. Wafers rotated so the damaged pole is at S5.3R and used in the AVC circuit where the make-before-break facility is not needed. To accommodate the wires and simplify the wiring somewhat, the pole use has also been reorganised:
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..
| Assessment
| Unit N16 Log
| Unit N0115 Log
| Unit N0144 Log
| Unit N0714 Log
| ..
Racal RA-17 & RA-117 |
bhilpert |