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tabbypurr@gmail.com: Aug 06 05:30AM -0700 On Thursday, 3 August 2017 12:35:57 UTC+1, John-Del wrote:   > If you're referring to the resistance line cord in my example, there aren't many options even if you don't care about originality (I don't). That radio in my example has 5 tubes, two IF XFRs, a gang tuner and a dynamic speaker all crammed into a 4X10 chassis pan. The plastic cabinet covers this like a glove. There's simply no room to mount a 25W resistor or mitigate the heat that it produces.   > Still, in the trade, the resistive AC line cord was known as a "curtain burners" because people would often coil them up in a neat little ball instead of spreading them out as the owner's manual directed.   > I do restore an occasional antique radio for my customers, and even after adding fuses and polarized line cords to them, I instruct them on the dangers of line connected metal chassis and never plug in the radio if one of the plastic knobs falls off. I also instruct them to leave all old radios unplugged when not in use and to not leave them running unattended.   The logical option with curtain burner sets is to build a separate psu to plug them into. Use a plug that can't go into any of the usual mains adaptors.     NT

tabbypurr@gmail.com: Aug 06 05:38AM -0700 On Friday, 4 August 2017 04:07:32 UTC+1, Phil Allison wrote:   > The caps used in hot chassis radios and TVs were all special high voltage ceramics rated for the task.   > .... Phil   I've got sets like that from pre-war onward, none of those caps are ceramic, all paper. Safer caps came later. I'm sure there were a lot of live aerials around at one time.     NT

John-Del <ohger1s@gmail.com>: Aug 06 07:10AM -0700 > > .... Phil   > I've got sets like that from pre-war onward, none of those caps are ceramic, all paper. Safer caps came later. I'm sure there were a lot of live aerials around at one time.   > NT     That's true on this side of the pond, but Phil is on the other hemisphere. For all we know they may have used ceramic caps instead of paper in live chassis.

Mike Coon <gravity@mjcoon.plus.com>: Aug 06 03:16PM +0100 In article <739e1231-8ffa-4cb5-8ee2-1996428e3f0a@googlegroups.com>, ohger1s@gmail.com says...   > That's true on this side of the pond, but Phil is on the other hemisphere. For all we know they may have used ceramic caps instead of paper in live chassis.   All this talk of ponds and transformers reminds me...   Years ago a colleague sold me (for a trivial sum) a Bell & Howell "Slide Cube?" 35mm transparency projector (which I still have; model 981Q). It was made for the US market, so I also got a 500W autotransformer to power it from the UK mains.   This made the kit very unwieldy, so I set out to convert it for 240V. Swapping out the 500W lamp was easy, and getting a 240V fan motor not too tough (though fitting it into the housing was trickier). But the optical path included an automatic focus adjustment, and the electronics needed a low voltage supply. It turned out that this had been supplied by a secondary winding on the fan motor, and of course my replacement fan did not include this. So I had to shoe-horn a small mains transformer (no readily available switch-mode supplies back then) in as well. But it did work, and I may pluck up courage to see if it still does!   Beware motors masquerading as transformers!   A small postscript. A yachting magazine had an article about isolation of marina power supplies for boats, both for safety and for prevention of galvanic corrosion of underwater parts. But they mentioned the use of an "autotransformer". Since I owned one, I was sensitive to the fact that this would not provide isolation and could be dangerous, so I wrote to the magazine. I am happy to report that they published the correction!   Mike.

tabbypurr@gmail.com: Aug 06 05:42AM -0700 On Wednesday, 2 August 2017 03:22:34 UTC+1, Andy Burns wrote:   > Depending where you live ... methylene chloride strippers are banned > here apart from for professional use, as a result you might as well use > porridge for paint stripper now.   It isn't, it's just not allowed to be marketed as paint stripper.     NT

Andy Burns <usenet@andyburns.uk>: Aug 06 02:00PM +0100 >> methylene chloride strippers are banned here apart from for >> professional use > > It isn't, it's just not allowed to be marketed as paint stripper.   That's why I didn't say "methylene chloride is banned here", see above for what I did actually say, and whether you disagree with that.

mhooker32@gmail.com: Aug 05 06:58PM -0700 > > im thinking the added cable adds a load that stabilizes the horz sync, and maybe there is a way to make it more stable? there is only h sync out, no vert. vertically, there is no jitter   > > thanks   > correction. with the spare vga cable, it still is 90% better. the second time i plugged the spare into a second card i had on the bench, like a schmuck. plugging into the right card, and its close   i put a 4.7 k resistor in line with the sync and it seems to be fine now, no dummy vga cable needed. i tried different values, 4.7k works well.

Tim Schwartz <tim@bristolnj.com>: Aug 06 07:52AM -0400 Good morning,   While you have seemed to have fixed your problem, you could have considered posting the make, model and part number of the flat panel you needed, as there are plenty of people who have old, obsolete parts around the shop that they are thrilled to see get used.   While that does not mean that this should become a parts for sale site, it is also not a terrible thing to ask about a part on occasion.   Regards, Tim

Tony <nomail@nospam.com>: Aug 06 09:07AM +0800 Hi, it may be a long shot:   Has anyone come across this problem? Only FM works. Main supply voltage OK. It's not the antenna switch.   Also, where do I get schematics/service manual? I found a copy but hardly readable.   Cheers   Tony

Phil Allison <pallison49@gmail.com>: Aug 05 09:17PM -0700 Tony wrote:   -----------------   > Hi, it may be a long shot:   ** A couple of minutes with Google turned up this:   http://www.eham.net/reviews/detail/525   See the second post.   Seems loss of all AM bands is a common fault caused by a dodgy trim cap - C138.       ..... Phil

Tony <nomail@nospam.com>: Aug 06 05:00PM +0800 On 06-Aug-17 12:17 PM, Phil Allison wrote:   > Seems loss of all AM bands is a common fault caused by a dodgy trim cap - C138.   > ..... Phil   Thanks Phil, I read right past this clue and missed it. However, it was not C138, but another one nearby, C130. They are not on the RF board but on the processor board underneath (in a can...).   It's easily identified by the fact that it is actually accessible through a hole in the RF-PCB above and in the can below. There is a handy hint for any one chasing this fault!   If one doesn't want to go so far and actually replace this trim C there would be *no need* to take out the RF board, unsolder and bend out the 4 lugs of the shield cover of the processor boards and so on, a real PIA. Just reaching through the hole with a trim tool and lightly tapping on the variable cap is a quick fix. Good enough for me for now, I'll see how it goes. But if one needs to replace the lithium memory battery there is no way around this awkward job though.   Tony

lmmcams@gmail.com: Aug 06 12:11AM -0700 Thanks for this, they certainly don't react as diodes. But after some investigation, I have found they are wired as pairs and can be made to work but it's taking a lot of fiddling.   Also iPhone and iPads don't show ir:-(   Oh well, bodge away I shall.   Steve

"Michael A. Terrell" <mike.terrell@earthlink.net>: Aug 06 03:10AM -0400 > Whoooo Boy! I can think of no reason whatsoever that one should ever use a VTVM in these modern times. Sure, loading a Zenith TransOceanic while performing an alignment via a VTVM makes some of the things go 'by the book', but using a regular high-quality VOM is just fine.   A VTVM has a 1 megohm resistor right at the DC probe tip to isolate the cable capacitance from the circuit being tested. Of course YOU would never think of using the right equipment.   You never do any precision work, so any old crap meter is fine, for you.   You don't care about detuning an RF or IF stage, or shifting the L.O.way off frequency.     -- Never piss off an Engineer!   They don't get mad.   They don't get even.   They go for over unity! ;-)

"Michael A. Terrell" <mike.terrell@earthlink.net>: Aug 06 02:56AM -0400 > That was back when things took a bit of effort. I can't stand new shows, with their video tricks you think the telly is fucked up and needs service. Fucked up color, green and white like a bad CRT. Jiggling, rolling and all that. the broadcasting equipment used to be designed to avoid that, that's why they had genlock.   > I can't stand new TV or movies. So much special effects, guys jumping fifty feet up in the air and all that shit. Where's the goddam plot ? What was this all about anyway ?   > But that is the way it goes, every year there is less and less keeping me here.       Genlock? TV stations had one or maybe two sync generators. If they had two, there was either a manual, or automatic fail over function.The video would jump to any external sync, if the input was used to attempt 'genlock'. That was how I transmitted a color ID from a B&W TV station in the early '70s. For those who don't know, the H and V sweep was slightly different for Monochrome and Color. I fed the output of a Heathkit color bar generator into the sync generators, as well as the video input on the crude RCA keying function of the Monochrome video router. I also disabled the TV transmitter's chroma trap which was used to prevent color TVs from trying to lock onto noise in the colorburst range of 3,579,545 Hz. I did all of this, to prove that the station could be converted to color.     -- Never piss off an Engineer!   They don't get mad.   They don't get even.   They go for over unity! ;-)

"Michael A. Terrell" <mike.terrell@earthlink.net>: Aug 06 02:58AM -0400 N_Cook wrote:   > No mention of an interociter yet though     Lucas couldn't get a license to build Interociters.   -- Never piss off an Engineer!   They don't get mad.   They don't get even.   They go for over unity! ;-)

"Gareth Magennis" <soundserviceleeds@outlook.com>: Aug 05 07:51PM +0100 "Gareth Magennis" wrote in message news:_v4hB.468124$YV4.166073@fx18.am4...       wrote in message news:30addb86-d420-4d3d-91e1-acd2ffe4f1a2@googlegroups.com...   How much power is this thing ? If it is not too high you can just rewire it to use a pair of LM3886 or something. They are not bad chips. I did that a year or two ago on a unit that used an SVI chip, which is an STK but just considered fancy.       ***********************************************************************       I now think it would make more sense to use another cheap, easily available STK module. They are pin for pin compatible and bolt straight onto the heatsink. 10 minutes to change them.   The 2 x LM or TDA options are going to mean an absolute rat's nest of wiring to individual IC pins in mid air, not to mention having to sort out a suitable mute conversion. How many hours is that going to take?       Gareth.         *********************************************************************   Well, having ordered a STK 442-120 and expecting it to arrive in 2 days max as usual, it didn't. Wasn't even dispatched until friday, I assume half the staff are probably on holiday. Most unusual.   Anyway I decided to have a look at using a pair of LM's/TDA's or whatever, only to find a new STK 442-130 in my TDA drawer I didn't know I had. I must have ordered two some time in the distant past and gave myself a spare.     So, swapping them out really was very quick, and it works. I believe these 130 version are rated 150W, but I've no idea what they base this upon, as it is probably bogus. The Onkyo I have doesn't look hugely powerful power supply wise, so this IC is probably well overkill over the original, whose specs I could not find anywhere.   Check out the prices of these, they are not expensive. I even found a US retailer who were guaranteeing theirs were genuine Sanyo parts.         Another thing. This Onkyo has 2 STK parts, the 442 and a 443 part. The 443 part has 3 amplifiers, the 442 has 2. Consequently the 443 has more pins. It turns out that the pinout for the 443 follows exactly the 14 pins of the 442, and simply tacks on an extra 4 pins for the 3rd amp (2 in, 2out).   The motherboard of this Onkyo actually has 18 pins available at the site the 442 was occupying, with circuitry not fitted regarding a possible third amplifier. Meaning it was a generic motherboard that could use either 2 x 443 chips, or 1 x 443 and 1 x 442, depending on which model it went into.     So this leads me to believe that these STK chips are indeed simply plug and play, you select the particular chip with regards to how many amplifiers you want and at what power.   Which is why people like Onkyo use them? It would make sense to know you could produce a generic PCB and simply plug in whatever STK's were appropriate in a single design, and that any future improved STK's could simply be plugged in instead without any major redesign work.     Anyway, for not much more that a couple of LM/TDA's, you could perhaps just find an appropriate STK, you just need to find a reliable source of these.     Good luck, I don't do hi-fi repairs, this is a very good example of why not.         Cheers,     Gareth.

John-Del <ohger1s@gmail.com>: Aug 05 12:45PM -0700 On Saturday, August 5, 2017 at 2:51:53 PM UTC-4, Gareth Magennis wrote:   > only to find a new STK 442-130 in my TDA drawer I didn't know I had. > I must have ordered two some time in the distant past and gave myself a > spare.   Here's something you probably don't realize: if you didn't order the -120 the -130 would have remained hidden. I don't understand the physics of it but it's best to just admit this stuff happens (plus, you'll feel better)..

"Gareth Magennis" <soundserviceleeds@outlook.com>: Aug 05 10:44PM +0100 "John-Del" wrote in message news:ef2429a7-7279-4f17-8c6b-9063186f1c7b@googlegroups.com...   On Saturday, August 5, 2017 at 2:51:53 PM UTC-4, Gareth Magennis wrote:   > only to find a new STK 442-130 in my TDA drawer I didn't know I had. > I must have ordered two some time in the distant past and gave myself a > spare.   Here's something you probably don't realize: if you didn't order the -120 the -130 would have remained hidden. I don't understand the physics of it but it's best to just admit this stuff happens (plus, you'll feel better)..     **************************************************************   Yep, I get that. :)   I also no longer get annoyed on the road when I take a wrong turning, or get lost. I say to myself, that might well have saved me having that fatal accident.       Gareth.

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