Manufacturer: Hewlett-Packard Model: 7970A MOD 202 (37.5 IPS) Serial No.: 1048A-00475 Year of Manufacture: Most component date stamps are from late-1970 to mid-1971. Power supply regulator board has dates up to mid-1972. Other ID: Sticker inside with "Marine Sciences Branch, Dept E. M. & R.: Pacific Region" (Canadian Department of Energy, Mines and Resources).   Received: September 2003 Source: Thru SPARC. State upon Receipt: Load switch broken/loose from being banged sideways, bezel for lamps and switches missing, dusty dirt from storage, two or three curious spots of powdery build up (one on tape head), tape reels seized on hubs, otherwise good condition, minimal scratches.

Notes:

• Tension arm lamps: IEE 328 6V (?mA@6V measured externally, operate in unit at ~2V)
• Load point lamp: 428 (210mA@6V measured externally, operates in unit at 5V,190mA)
• Unit Selector lamps: IEE 382 14V (75mA@14V measured externally, operates in unit at 12V)
• Available: Schematic for capstan motor driver board.

Repairs:

10 Nov 2003:	Tape reels seized on hubs. Soft rubber on hubs has attached itself to the reels. Two 4-40 screws which keep hub mounting tabs from rotating broken in process of removal. Screws replaced. Should not leave reels mounted for extended periods.
10 Nov 2003:	Cleaned up. Broken load switch fixed. Load point sensor lamp replaced with 328 (GE).
10 Nov 2003:	Tape will not load. Tape simply rewinds off take-up reel when LOAD switch is held down. Reel motors/tension arms servo behaviour appears to be fine when no tape is present during load. However, capstan motor is constantly on (rewinding) during load. 100 Ohm resistor around Q6 (2N3715) fried on capstan board. Q5 both junctions shorted. Q6 BC short, BE open. Other transistors measure OK.
12 Nov 2003:	Q5 and Q6, 100 Ohm resistor replaced, same results.
12 Nov 2003:	0.83 Ohm resistor in -12V regulator has large crack. Measures OK.
13 Nov 2003:	Reverse-voltage ground-clamp diodes on +/-20V supplies appear to be poorly installed field modifications. Diode on +20V had come loose. Resoldered.
13 Nov 2003:	Capstan board powered up in test set-up, erratic activity found around Q1-collector/Q3-base. Q1 (2N2218) replaced with surplus 2N2219. Activity more stable. With original back in, still stable. Q1 presumed intermittent regardless. Q5, Q6 replaced again with 2N3055. Q1 replaced with 2N2219. 100 Ohm resistor replaced again. 1K base bias resistor for Q4 replaced due to proximity to heat of 100 Ohm resistor when it burned up. Unit now functional to extent of loading and rewinding tape properly. (2N3055 compatible with 2N3715 except for lower power rating, hope they survive.)
30 May 2003:	One roller slightly sticky, dismantled for cleaning, small drop of light oil placed in bearings.