Hi Zeerust!

As you can see we're all anxious to help!!

Read my post in Vintage TV on restoring Pete's TV - in particular about bringing up old gear using the dim bulb technique. IMHO (as an engineer) it's safer and kinder than a variac and a hell of a lot cheaper!

In that example, had I not been impatient and left the chassis on the dim bulb longer I might not have killed the electro - although in retrospect, looking at them after they were removed from the chassis they were well past their use-by date anyway.

I doubt you will have any trouble bringing up that chassis though, it's relatively new (no paper caps, better quality electros) and I'm tipping that it will work for you straight away with a 100 watt lamp in series.

Thanks again Ian. I intend to make myself a dim bulb tester before firing up this unit. I gather the aim is to limit the current that will flow in the event of a serious short in the circuit. From what I can gather, the tungsten filament bulb is an old fashioned incandescent bulb. These seem to be hard to find, and I'm not at all sure I could legally import them into Australia via ebay. So, do you have any advice on where I can find these bulbs, or if one of those newfangled halogen bulbs of the same wattage would have the same function? Cheers.

Filament light globes are becoming very rare now but can still be purchased in most of the non-standard varieties at Big W and Bunnings. When using globes for limiting current the style doesn't matter, only the power rating of the globe. 60W will let through 250mA, for example.

Globes such as the candle shape and fancy round usually come with a maximum rating of 40W. Another handy rating is 25W and any or all can be put in a series and/or parallel arrangement to get the wattage you desire. All the decorative styles can still be got with standard bayonet bases.

I think most halogen globes (where the quartz jacket is mounted inside a standard glass one) come with a rating of 48W. Why? Don't ask. The strange number is anyone's guess. I can't think of a reason why halogen globes couldn't be used for the same purpose though.

I still use 25W pilot globes in my test lamps when testing electrical circuits. There isn't a better method for testing hard wired circuits.

When one M Turnbull put the common household BC bulb on the death list, supermarkets put their stock holdings on discounts as much as 80% and I bought hundreds of 60W and 75W clear and pearl. I've got enough of them last out the decade or longer at normal usage hours.

So-called "fancy" incandescent bulbs (party lights, pilot lights, etc) were not put on the death list.

The dim bulb tester is essentially an illuminated resistor. Just put some "fancies" in parallel to make up the required wattage value.

Even though only the bigger globes were banned I have done much the same with pilot lamps because it isn't possible to correctly test a three phase installation with CFL or LED globes. The time-honoured halfglow-fullglow test results just won't work with them. I think I have about 40 pilot lamps in stock and at the current rate that I bugger a globe, that should see out my career with some to spare.

Future generations of tradesmen will be stuck using a meter. Quite satisfactory but somewhat slower.

I can see now that this Belatone is a rebadged Precedent.

On the subject of incandescent globes I recently found two brand new Australian made Embassy brand (G.J. Coles) 25 W BC in their packets at the Chester Hill Salvo's. Got 'em for a buck a piece. I reckon they are from the 1970's & spent the last forty year under a kitchen sink!!

That Belatone is a nice looking unit.

The question is: what will she sound like?

Thanks for the replies. So the wattage rating is the most essential requirement, regardless of the bulb type, and I can simply wire bulbs in series to get the wattage I want. I'm guessing that the advantage of an incandescent globe is that the brightness will vary with the current in a way that may not happen with LED or other globes? At any rate, as I understand it, apparently "GLS Halogen" globes are essentially incandescent globes in a halogen filled envelope, so I'll go with those. The Belatone certainly looks nice. Even the grill cloth is near perfect. We shall see how she sounds. It contains a Garrard 1000 turntable.

Providing the globe has a standard filament it should be good. CFLs are discharge lighting and will not provide the necessary ballast function and the electronically-driven LEDs are pretty much in the same boat.

I actually use a variac connected to a dim bulb tester . Is this a issue ?

I actually use a variac connected to a dim bulb tester

That's sort of a belts and braces approach.

The Variac allows you to bring the voltage up slowly and should be used in conjunction with an ammeter to keep an eye on current draw.

The dim bulb tester by itself provides full voltage to the load and is sort of a visible current limiter when the load is a full or near short circuit for too long.

It's more usual to use either one or the other, or one before the other: Dim bulb and then, if no shorts, use the Variac for a controlled application of voltage over time.

As has been mentioned elsewhere, the DBT method can be used to reform old electrolytics, but these days I prefer to use a Variac myself to bring things up slowly after repairs/replacements because I like to have control over the process.

Some will argue that the Variac method can cause "cathode stripping" in some valves. I haven't experienced that myself.

Thanks again for all the invaluable info. I'll be off to Bunnings and/or Jaycar to get some parts and hopefully fire this thing up over the weekend. Be prepared, though, for some questions on the Garrard turntable. I used one much like this all through the 70s, and they're not bad at all. I hope to get this one functioning if possible.

I have the Exploded View & Spare Parts List for Garrard models 1000 & 2000.

If required I can send a pdf copy of it to be attached to this thread.

Garrard 1000 & 2000 Turntable Service Data

Just correcting a little mistake - you put lamps in PARALLEL to increase the wattage. Two 60 watt lamps in parallel gives you 120 watts.

Yes you can use 240v halogens. I happen to have a cache of politically-incorrect light bulbs that were exchanged with compact fluros when Kevin Rudd was splashing our money around. I kept the old ones for some reason.....

But whatever it is, it must consist of a filament in a glass bottle!

Why a lamp is so much better than a variac is because the lamp functions as a PTC thermistor. It increases its resistance the more current you draw through it. So if something goes wrong, the current is automatically cut back, faster than a fuse and much faster than human reaction time - the lamp simply absorbs the fault current and lights up. If all is well and the radio etc. draws less power than the lamp rating, the lamp filament will cool, allowing more current through - usually enough for the device under test to operate normally.

If you have a shorted mains transformer output in your device, you can still cook its transformer with only 50 volts from a variac. There is just NO CHANCE of doing this with a lamp in series - try it some time! This is particularly the case with small transformers and switched mode power supplies.

Hey, I've had nearly 50 years experience doing this!

Getting back to the sound quality of that unit, the amp design is highly optimised for the small-ish speakers and cabinet. You could change it to the Kriesler circuit retaining the 6BM8s but it would probably not sound as good with those speakers.

As a new and keen technician I once tried to "improve" one of these - it was in a Precedent 3 in 1 - with bigger, better transformers and other changes such as full-range negative feedback. It was a failure, it really didn't sound as good as it had before. That circuit boosts the low end to make up for the small speakers.