ADA Microtube transformer wiring and fuse

[Yazoo]

I am going to build a single channel version of the ADA Microtube 100. I have the schematics but I can't work out how the mains wiring to the 2 transformers works. The mains fused wire is connected to a Pepi heat activated switch which in turn connects to a fuse block and this then connects to the power switch. If there are any Microtube owners out there, I would appreciate any guidance you can give me. Thanks in advance.

[antonis]

I'd suggest you to take guidance from a mains wiring qualified person rather than any Microtube owner..
(no offense to the last ones..)

[Yazoo]

I can see from the schematics that the mains neutral wire is connected directly to both transformers. The live wire goes through the Pepi switch as noted and then via a second fuse to the transformers and the problem is that the wiring for the fuse block is not given in detail.

I've attached an image below.

[anotherjim]

Seems like the fuse block routes the switched live from the panel switch to each of the primaries. What it doesn't show is the rating of the fuses and yes, you'll need someone or some document to tell you the type and rating of those fuses (I would expect there are 2 of them). It's all very belt & braces as there's also the thermal switch and a main inlet fuse on the back panel - do you know the inlet fuse rating?
If it was mine, I'd get on with the build and fit 500mA delay fuses.

A puzzle for me is part #362005 on the back. Some form of surge/noise suppressor or an auxiliary AC output socket? Whatever, it forms a handy connection lug to distribute the unswitched Neutral to transformers and front switch neon.

[Phoenix]

Part number #362005 is a panel mount type A (North American/Japanese) auxiliary outlet for daisy chaining other equipment.
Edit: seems it might actually be type B (3 pin), not particularly clear from that image, a schematic would be better.

The "Pepi" switch is just a resettable thermal switch (Pepi is just a brand name, you can use any other brand instead), likely 70°C (please confirm that value on the schematic).

[Yazoo]

Many thanks for this. The chassis mounted fuse is rated at 1.5 Amps (Slow Blow). The fuse on the fuse block is rated at 0.5 Amps.

So if I have got this right, the live AC goes via the main 1.5 Amp fuse in the panel mount fuse holder to the Pepi switch. This connects on the fuse block PCB to the wire (black - UL1007) going to the power switch (282016) on the front. This then goes back on the wire (Red UL1007) to the fuse block. The Toroid transformer is connected directly to this, but the block transformer which provides 12V and 170V for the valve/tube HT is connected via the 0.5 Amp fuse. Does that sound correct?

Thanks again, I've really been scratching my head on this one. Those extra connections on 362005 had me completely flummoxed until I saw a picture with the white AC socket on the back of the box.

[anotherjim]

Ah, only one fuse on the fuse block then it makes sense that is for tube supply primary.
I found some photos and that is a 3 pin auxiliary AC outlet on the back. The other switch next to the power switch is the tube HT standby switch..

[Yazoo]

OK I've got it built and it is all working. I am both pleased and very relieved. I got the main board fabricated in China and did the rest myself. Because I am only using one channel to put around 50W, the smaller board is a lot simpler. I was able to remove the 4053 used to to do the circuit switching between mono, stereo and bridged outputs.

Thanks for the help on working the power wiring out.