This must have been one of the last digital multimeters with nixies. It is a portable mains powered unit. The logic circuitry is TTL (transistor-transistor logic). Judging by the production dates on the ICs, it has been built in early 1974. The styling and design are quite different from the earlier Philips DVM's, such as the PM2433, the PM2420 and the PM2421. The meter has been made in Japan. The nixies are JRC brand, type B-5870ST. I bought this meter in March 2002.
Most of the circuitry is concentrated on two circuit boards: a digital circuit board containing all the TTL ICs, the range switches and the nixie tubes and an analogue circuit board containing opamps and a lot of trimpots.
When I studied the circuit boards, I found a familiar name on both of them: Takeda Riken. I knew they were a manufacturer of frequency counters, because I have a Takeda Riken counter with a nixie display. But I was surprised to see they apparently had been a supplier for Philips.
This IC had been replaced before. The original Toshiba TD3441AP had been replaced by a TI SN74141, production date 1973. I put an IC socket in its place in case it would ever fail again. After that, the display was OK, but most of the ranges were seriously out of callibration.
Regarding the number of trimpots, callibration is not something to do without a manual.
Fortunately, a year after I published this page, I received an email from someone who had the manual. He sent me a copy, so now it only takes the right time to make this meter swing again!