🔴 Solartron 7075 Minor Repairs and Testing - 7.5 Digit Multimeter Repair - No.789

[@andymouse]

Nice unit to have around...cheers.

[@johnas2004]

Nice repair! Couple of questions - 2:11 - is that bird song? Did Solartron use silver solder originally, I've not seen this mentioned in any service manuals. Does the Solartron use the same Sperry displays as the Datron (SP 353)?

[@zx8401ztv]

I thought only the old scopes with the white ceramic boards needed only silver solder. But i could be wrong lol.

[@TheDefpom]

Yes bird song, as far as solder no idea, but I like to use the good stuff on test gear, I don’t know about the display, it is some kind of vfd

[@rpbale]

Fun video. I have a couple of Solartron 7081 and one is giving me fits troubleshooting it. Your videos always inspire me.

[@TheDefpom]

If you get sick of trying to fix it, I will take it off your hands and dispose of it for you :-)

[@douro20]

8.5-digit meters can be temperamental if not well treated.

[@rpbale]

@@douro20 I already confirmed the two opto-couplers were bad. The memory was put in all backwards. All of it. All batteries are replaced. One bad tant took out one power regulator. New CMOS rewritten, new MCU, driver chip and memory. But, the screen won't display. Of course all works with a known good earthy logic board. Screens fines. But this unit can't have the good board. The board must be repaired. I picked up all the gear to read the logic. But can't figure it out. The two logic boards are different generations CMOS wiring, so, swapping is out.

[@MrTamhan]

Nice idea re the blob at the top, man. Need to finally recap my Solartron 7150 to reassemble

[@TheDefpom]

The solder flows through to the bottom pads too, so it ends up being soldered properly.

[@zx8401ztv]

Smashing repair :-D, i think scots precision voltage generator is brilliant, i'm sure i looked at the schematic for an early version and i was impressed. I was given an old fluke 111 bottom end meter, after i checked my pile of cheap multimeters i found them to be good enough for my uses. I have a few ancient 10V round metal ref chips LH0070-0H +/- 0.03%, never used and all my meters were set to that years back.

[@IanScottJohnston]

Cheers!.......you probably saw an old prototype on EEVBLOG, it's changed massively since then......different uP, DAC and Vref.

[@Daveyk021]

If you're reading ripple with the DVM it is not measuring in P-P correct? Don't we usually think of ripple in P-P?

[@stevefox3763]

Is that an accent some have in NZ or are you a Brit? you sound like a Londoner or Essex with a hint of New Zealand.

[@TheDefpom]

Originally from Sidcup in South-East London, and have been in NZ for 30 years

[@stevefox3763]

@@TheDefpom i thought you were londoner :) Im from South Woodford E18 (born in leytonstone E11) but unfortunately living in the dump Salisbury now, your, move was slightly better than mine ha ha.

[@abeleski]

@@stevefox3763 I don't know if living in Mount Doom is a better move :)

[@stevefox3763]

@@abeleski do you mean government paranoia over the kung flu?

[@informediatech-bruno5766]

defpoms: its always a capacitor i-padrehab: its never the coil louisrossman: dont delay F apple today paul daniels : humm...that american from new york informedia: "yeah one day ill be a youtuber"