This was one of my spare parts sets but I am rebuilding it now. It does work but it's a wonder. The rectifier was built using a old 6X5 base with the components sticking out the top. Bloody dangerous , the guy also terminated a 100UF electro onto one of the existing 16UF electros keeping it in circuit, again not good so its reverse engineering for me on this one.

The rectifier was built using a old 6X5 base with the components sticking out the top.

Putting silicon diodes onto a rectifier valve base is not an uncommon hack. However, apart from a higher B+ voltage which needs to be accommodated by a dropping resistor, the 'instant-on' of silicon can have deleterious side effects if the rest of the circuit doesn't want B+ on the valves before their heaters warm up.

Nonetheless, leaving the rectifier diode leads uncovered is very poor practice. Exposed HT connections belong below the chassis, not above it.

Hello all.

Back when I repaired B&W TV's for a living, one could buy plug-in a solid state replacement for the 6N3 valve, and for 1S2 valves.
The 6N3 replacement had a large heat dissipating, dropping resistor.

The solid state replacement for the 1S2 was used to bypass a socket, heater loop whose insulation had broken down.
There was also a version without the the insulated base which was a direct plug in replacement for when the socket/heater loop did not need replacement.


Wayne.

If it originally had a metal rectifier, it would indeed, develop more volts but still behave like a 5Y3 and create a surge voltage close to twice the loaded volts, so one has to watch the voltage rating of the caps.

If there is concern re the inrush current one can add a series resistor before the diodes., as some did with 6X5. If you add a series resistor DC side, by not using a cap on the diode side, that will act a s a choke input filter & produce less volts.

Digressing: I have a fuse of around 160mA in the PSU / Reformer's B+. If the reformer is switched in with live B+ the 10μF cap on the reformer side of the switch is enough to blow it.

Marc

This set has now been recapped and is working but not enough volume. When I connect a antenna wire reception gets a little stronger but when I touch one tag on the tubing capacitor it comes on strong. Could this mean there is a resistor in the antenna circuit that's gone high or is it just a realignment. This set has been got at but is worth repairing and when it's complete I will have two model 114s.

Photos uploaded to Posts 1 and 3.

Sounds like it needs an antenna coil alignment as minimum.
One of the two beehive tuning caps seen in the images will be the aerial coil peaking adjustment.
Have the dial at approx 1400kHz for this adjustment.
Adjust for max noise/output.
To establish which is the aerial cap or the oscillator cap, just tune to a station and rock cap.
If station goes off tune put it back to where it was, that’s the oscillator tuning. And not the one to peak at this stage.
Sometimes if you don’t do a lot of this type of work it pays to read and follow the manufacturers alignment procedure.
But some instructions also assume you know what you are doing, and are just generic so to speak.
Did you also check all the high value resistors.
Hope this helps. JJ

No not all the high value resistors, just the ones on the output valve. I found two resistors that must have been add ones and served no real purpose as they did nothing what so ever.

That body end for resistor in my last photo on the bottom right went high as I was testing it. Even though it measured within tolerance I was sceptical and placed another resistor over it to lower the value and it just went off as I did that. I replaced it with a new 470 k and it made a world of difference.

As noted I prefer to check resistors as I change caps. The highest attrition rate are 50K, 500K & quite often 100K and the plate resistors on the first audio (all high ones as for previous post). If you have an eye tube, that normally has a 1M resistor on the base and its rare to find a good one.

As I commercial fix 10% is the toss out point: NP caps that leak (and I don't care as to the extent) are duds.

It is recommended by the majority of manufacturer's to recalibrate the RF if you change parts. Over time coils can also change. Watch out as to how much signal strength you use. Where there is AGC, if you use too much IF signal, AGC will cut in and you will never get it right. I will not trim the Antenna with a Generator coupled: That throws it off.

Back to that 6X5 adapter with the Si diodes.....should not the original constructor pumped silicone over the components....we all have a tube of that in our garage...don't we?

Silicon is a very bad insulator in general.
No doubt there are some types especially made for the purpose, but not so the normal stuff.
In my experience have had many instances of silicon applied by servicemen failing in a burning way!
OK for keeping water out of 12 volt equipment, but usually only a temporary fix.
JJ

Some silicons are guaranteed for 20years.

I have heard that the "neutral cure" version is the way to go.