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IZ3LSV

[San Dona' di P. JN]

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G8MNY  > TECH     13.08.20 08:45l 43 Lines 1559 Bytes #999 (0) @ GBR
BID : 1255_GB7CIP
Read: GUEST
Subj: Maplin 13A Socket Mains Tester
Path: IZ3LSV<IQ5KG<IK1NHL<CX2SA<PE1RRR<CT1EBQ<PY2BIL<GB7YEW<GB7CIP
Sent: 200813/0620Z @:GB7CIP.#32.GBR.EURO #:1255 [Caterham Surrey GBR] $:1255_GB
From: G8MNY@GB7CIP.#32.GBR.EURO
To  : TECH@GBR

By G8MNY                                (Updated Mar 20)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)

This is a 230V AC 3 neon plug in safety tester. It can only detect simple
wiring faults!

Inside there is 2 PCBs with the Neons (DS1-3) & 8 Rs.

LiveÄÄÄÂÄÄÄÂÄÄÄÄÄÂÄÄÄÂÄÄÄÄÄÂÄÄÄ¿
       R1 DS1   R4  DS2   R7  DS3
      56K (=)   82K (=)   68K (=)          * * *  Mains OK
       ÀÄÄÄ´     ÀÄÄÄ´     ÀÄÄÄ´           * * .  No Earth
          R2         ³         ³           * . .  Live or Neutral reverse
          82K       R5         ³           . * *  No Neutral
NeutralÄÄÄÄ´        68K        ³           . . *  Live or Earth reverse
          R3         ³         ³           . . .  No Live
          33K        ³        R8
           ÃÄÄÄÄÄÄÄÄÄÙ        82K
          R6                   ³
          33K                  ³
EarthÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ

I took mine apart after DS3 started to flicker & then went permently out!
On testing with an isolation transfomer fed from a variac. I found all it
worked properly on 260V. For some reasion the attenuation differences in DS1 &
DS3 feed Rs seems to be wrong. Isolating the Rs they are all quite nominal &
swapping the neon around did not move the fault.

So I replaced R7 & R1 with 100Ks, and it all works correctly now all 3 neons
extinguish near 210V, & the various fault indication functions all tested OK.


See my tech bul, "Maplin Mains Meter 2000MU-UK"


Why don't U send an interesting bul?

73 De John, G8MNY @ GB7CIP



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