"The MIDGET-7 called 'electro-wave test oscillator' is smallest among the ones which have sufficient function. It provides small size, light weight, which enables a serviceman to work not only at his bench but also everywhere he goes. This is amazingly convenient for lots of use."
(Sanwa, Translation of japanese manual)
BRIEF SPECS
| Frequency Range | 100Kc ~ 30Mc |
| Modulation | appr. 400 cycles |
| Accuracy | 1% |
| Power | 100V~ |
| Dimensions | 17 cm x 24 cm x 14 cm |
| Weight | 2 kg |
| Technology | tube |
| Price | unknown |
Sanwa's Midget-7 is a good example of low-cost instruments which were used by radio repair shops. Similar models of Eico or Hickok wer priced around 50 US$ (which is approx. 3 percent of a hp 606 !). Commonly these instruments had quite simple circuitry without any special attributes.
The Midget-7 has a rectifier tube (type KX-12F) and one pentode (type VZ-6C6) which serves as rf oscillator as well as af modulator. The output is not calibrated and I think accuracy was only fair enough to test consumer radios of the day.
I rewired all of the circuit as the preowner(s) did not hesitate to modify the instrument. One of my friends in Asia translated the 'manual', so I am able to publish some few data. There is no print date in the manual but I think it may be from the late fifties. Sanwa is still in the T&M buisness and has a nice range of professional DMM's similar to Fluke, but it seems they serve mainly their local market.
