One thing: Whilst I have two Slide transformers, one Jaycar (China) and a Dimmerstat (India, beautiful bit of work). It is a rare thing here for them to be used on a radio start up. Do not have a "Dim bulb".

Hi Robbert.

No need to apologies, I have only learned what I know through people like you and others on this forum and other blogs/groups etc.

It is best to play it safe, one never stops learning.

Thanks I have noted your point regarding the bias, certainly do not wanted to shorten the life of this 6BV7.
Great that your clock still works, did you do any work on it?

I will update on this post how I go with the Chassis work, hopefully sometime next week.

Hi Marcc,

In relation to Re-Alignment, I do it on an as need basis, must admit is not that often, but I could be missing out on more improved sensitivity. I may experiment with before and after alignment on set I would normally not Align.

I always believe in grounding the set with a new 3 core power cable, though I have heard some sets do not perform well when you do this but I cannot recall which ones and why?

Hi Marcc,
Regarding Radio startup, with you many years of working on radios, I was interested to hear you do not bother with the Dim-Bulb or slow voltage ramp up.

I gather I am being quite cautious as a relative newbie to this hobby?

Great that your clock still works, did you do any work on it?

No, I don't touch clocks. I have a number of radios with clocks (AWA, Philips, STC), but only 2 work, these being the Philips and the 461MA. Carl gave me a spare working AWA clock, but I've still yet to put it in a radio.

Guys.

With any unknown set, with repairs, or even a new build with unformed electros, I ramp up slowly with the Variac and keep an eye on the wattage drawn.
I check component temperatures, look for smoke or fire, until capacitor charging has finished, and wattage has settled.

This is simply good workshop practice.
Why anybody would advocate bad practice is beyond me.

I take no part in any debate of the merits of either dim bulb or Variac such argument is infantile.
I don't care if you use a bulb, a Variac or your wangdoodle.

Ignoring precautions is daft and stupid.
I have powered up equipment and ignored the precautions, and had electros or resistors vent expensive smoke, valves arc internally and so have been both daft and stupid. That means I am qualified to have an opinion and move up the Dunning Kruger curve a bit more!

Let's all have a bit of science and good practice with our hobby and get off silly 'hobby horses'.

Cheers, Fred.

I have due to failures adopted a policy of checking the electrolytic caps on a reformer, as I don't know how long they have been in storage. That way I get the dud before I use it.

I do Tag & Test now, but have never powered a radio that I consider unsafe to do so, and I have had some horror mains wiring, and cables in my life.

I do not bother with a "dim bulb" as in 99% of cases, step one for a radio, is not powering it to see if it goes. It needs assessing before you do that, be it Mains, or Battery. Most of the time you have to do testing & repairs anyway, before you can power.

I consider that in close to 60years and hundreds of radios. I have usually eliminated the horrors before powering. Tubes are tested externally, so its rare to get a shorted one. Transformers are tested as for Tag & Test and the primary wires are made compliant, if it will repair. Other than primary side, I will check the transformer secondaries, to make sure they do not have earth leakage, or they have shorted into one another, or are open circuit. Failures are rare.

Like many manufacturers of the era (Astor being one), as I check the wiring I will dob the joint with a paint marker, so, unlike a few, I don't miss any unsoldered etc.

Start-up of a tube radio is done monitoring the B+ and via an Isolation transformer (if mains). This is only 3A but has circuit breakers primary and secondary for its protection. In other words that downrates it from the mains circuit breakers and I will not use conventional wire fuses in it, as I have seen too many wire types, prove ineffective.

This Isolation transformer has a "Kill Switch": So, in the rare, event of something going wrong, I can kill the circuit faster than any conventional switch.

The kill switch is not as fast nor effective as a "Dim Bulb" setup.
I cannot believe a knowledgeable technician would not endorse instant current limiting.
I speak of thousands of repairs and around 65 years in the actual industry.
JJ

JJ, I concur.

Not only does a dim bulb kill the over-current quicker than anyone's reflexes can, in milliseconds which is even quicker than a fuse, it also does it when you are out of the room!

I may be lucky, but you make your own by due diligence.

I did have a dim bulb years ago but for decades I have not seen the need for one. By monitoring B+ I can pretty much tell if there is an issue and have never cooked anything on startup, nor got a transformer to smoke. The mains side will not be powered untested.

I follow Sony's policy & "burn test" for a minimum of three hours. That, according to their statistics is where the highest percentile of failures will occur.

With burn test, or running something that has a high risk of failing, leaving it unattended is bad practice. The mechanical work shed here is 50m away and the office, electrical repairs & computer shed, is 15m from the house.