sci.electronics.repair@googlegroups.com

Google Groups

avagadro7@gmail.com: Aug 12 08:09AM -0700 NOT building a Dell with fan access doors suggests Dell cooling fans or fans generally run on but my fan did not....I dunno the stats on cooling but we are here...   the larger room fans run on....

Phil Allison <pallison49@gmail.com>: Aug 12 12:09AM -0700 Hi,   a Marantz ST300 arrived in good cosmetic condition and all lights working - but no audio from either AM or FM. Problem turned out to be the 28 pin IC at the heart of the unit has gone AWOL.   It's a distinctive looking sod with a metal grounding tab at one end - as indicated by a few pics found on the net.   But what is the number ?   Reckon it likely starts with "TDA..... "       ... Phil

jurb6006@gmail.com: Aug 12 01:15AM -0700 >"Reckon it likely starts with "TDA..... "   Yeah, then you find it and find out you can't get quadrature, or itwon't ocne out of muting even with the switch. Or won't mute.   They weren't quite into change for the sake of a buck like today, but they did have the idea to be exclusive. that is why the "audiophools" for more for the 1970s stuff. Some of it did sound just as good or better, and there were practically no ICs. This shit can be fixed until the end of time.

Tim Schwartz <tim@bristolnj.com>: Aug 12 08:16AM -0400 On 8/12/2015 3:09 AM, Phil Allison wrote:   > Reckon it likely starts with "TDA..... "   > ... Phil   Good Morning Phil,   According to the service manual, Q206 is a AN7000. (Marantz pert number HC10009020)   Good luck in your quest.   Regards, Tim Bristol Electronics

Nick <someone@invalid.inet>: Aug 11 07:51PM I've got an Arcam Alpha 8 CD player with a somewhat tired laser, the player has started to skip on occasion and checking the RF (eye pattern) shows that the levels are a bit low. Cleaning hasn't improved matters.   I understand that these laser units haven't been made for a number of years but there are many 'clones' available. I've now tried two different replacements and quite honestly they seem to be pretty poor, in both cases the sled rack doesn't 'mesh' at all well with the drive pinion which doesn't inspire much confidence!   In terms of electrical performance the first (labelled as NKS210A) 'sort of' worked but checking the RF showed gross distortion and the player skipped in the presence of the slightest surface damage on the CD. The second (labelled as KSS210A), gave a much better eye pattern (levels 'OK' / clean and undistorted) and plays fine except for two CDs where it has 'issues' (both of these played fine with the original laser assembly!)   Looking on Ebay there are a multitude of different KSS240A lasers for sale at differing prices, are there any known good ones to go for?   I also see some sellers have listings like: 'Laserpickup, Original Sony KSS240A'. Is it possible (likely) that these could be genuine Sony laser assemblies? Is there an easy way to tell a fake from an original?   Any ideas?   Nick

jurb6006@gmail.com: Aug 11 02:50PM -0700 Not sure but you might be able to get them through a place called Asti Magnetics. I don't have their new phone number since they were bought out by EVG. I used to be on their mailing list and I recall seeing a list/cross for C pickups. Thee "magnetics" part is from when they specialized in after market transformers for TVs. Then they went into video heads for a while.   I have no idea of their sources but their products were usually good. The problematic ones were not just problematic for them. Certain things are just troublesome it seems.

"Arfa Daily" <arfa.daily@ntlworld.com>: Aug 12 01:44AM +0100 "Nick" <someone@invalid.inet> wrote in message news:mqdjnv$g6v$1@dont-email.me... > assemblies? Is there an easy way to tell a fake from an original?   > Any ideas?   > Nick   I'm a bit confused. You start off talking about a '240, and then continue with the story of having tried two variants of a '210, before returning to discussing the '240 again at the end. 210's and 240's are quite different animals ...   As to replacing a KSS240A, I have to tell you that I have had pretty much zero success with replacements for the last 5 years or so, and these days don't even bother wasting my money getting one in for a job. As to the places offering "Genuine" or "Original" Sony pickups, I haven't found one yet that is. In fact, a while back, I had a long argument with an eBay supplier who advertised an original Sony KSS240 and even had the photo on the listing of the genuine article, with the Sony logo on the lens surround. Because of this, and the experience I'd previously had, I chose this supplier for the exact reason that they *were* offering a genuine replacement. When it arrived, it was nothing of the sort. Just for sport, I tried it in the player, and as expected, it behaved worse than the one it was replacing.   I took it up with the supplier and eventually, after a lot of to-ing and fro-ing got a refund, and got him to change the listing.   240's have, in my experience, always been a very fussy laser anyway, but never more so than with the clones that you now get. In fact, the whole laser replacement situation has taken a real nose-dive in regard to KSS series ones over the last couple of years, and for the most part, I don't even bother replacing 213s any more. Some work ok, some not so well, so not worth the risk. Interestingly though, I have had no problems with the replacement Sanyo ones (SFP101N both varieties, and usually supplied as a complete deck) and Philips VAM 12 / CDM12 varieties.   As to telling 'fakes', the originals always had the Sony logo on the lens surround, always had a small sticker indicating the laser diode current that had been set to give the specified output, and always had the pot - or pots in the case of a '240 - sealed with either white or yellow paint.   Not very good news for getting your Arcam working, I'm afraid, but just my experience changing lasers professionally for many years. I'm sure that there are a few others on here that can add to what I've said with their own experiences.   Arfa

Nick <someone@invalid.inet>: Aug 12 08:02AM On Wed, 12 Aug 2015 01:44:01 +0100, Arfa Daily wrote:   > that there are a few others on here that can add to what I've said with > their own experiences.   > Arfa   Hi Arfa,   Sorry for the confusion - I did mean 'KSS240' (and NKS240), just a brain fart when typing.   I looks like the Arcam is destined for the great recycling centre then :- ( A bit of a shame as in all other respects it works fine and I'm quite happy with the sound. I didn't 'think' it was that old, but looking at the transport it does have a date stamp of July 1998. As I purchased it from new maybe it hasn't done so badly after all!   In the name of 'sport' I might just contact one of the Ebay sellers that is claiming 'original' KSS240s and specifically ask if it is a real one or not - certainly the picture looks 'right' (The adjustment pots are sealed with yellow paint, and the main flexi socket looks the same as on my original unit)   In the meantime I guess I'll start researching a suitable replacement for the Alpha.   Many thanks again   Nick

Nick <someone@invalid.inet>: Aug 12 08:08AM On Tue, 11 Aug 2015 14:50:26 -0700, jurb6006 wrote:     > I have no idea of their sources but their products were usually good. > The problematic ones were not just problematic for them. Certain things > are just troublesome it seems.   Hi,   Thanks for the info - looks like they are based in the US, and from the website I'm not sure they ship to the UK / EU   Oh well   Nick

dansabrservices@yahoo.com: Aug 12 04:00AM -0700 I have 2 remaining NOS pickups: KSS240A and KSS240ARP. Both were acquired from my Sony parts distributor when I was a Sony repair center. I have never had a problem with parts from that source. I'm n the US and I don't know the shipping cost. but either or both are available.   Let me know if you are interested.   Dan

jurb6006@gmail.com: Aug 12 01:01AM -0700 Update :   https://dl.dropboxusercontent.com/u/29948706/33901.jpg   Now have calibrated distortion in via a matched set of resistors and an external generator. It measured 0.055 % on its own oscillator. I had a 10K rom that nd a 10K from the HP generator with 600 ohm output impedance.   I calibrated, which is to set the level so the needle goes to 100 % and then you switch the switch.   We found that even moving around the room affected the reading when we were reading that 0.0055 %. Also, because of my slight (only one order of magnitude) error, we were measuring 10 KHz, not 1 KHz. Of course all the filters were off, but I do want to try those filters.   I started to get close to the null frequency with the external generator. I saw how the response dropped.   The scope on the left was connected to the monitor, where you can see the TRMS meter input. I am about to chew through these ropes and get a spectrum analyzer to hook up there. The scope to the right has the original HP 339A output going to one channel and the output of the other HP generator sitting on top to the other channel. Thus it is easy to compare the amplitude of their waveforms.   When the amplitude was 25 %, the distortion meter read 25 %. I mean when the internal HP was 3 volts, and the external was 1.5 volts it read 50 % distortion. Since the TRMS convertor is after the input attenuator, is it not reasonable to assume that it will be accurate at different ranges ? that is determined by resistors just like every, and I mean every other thing on the planet.   Well there are exceptions...

"Arfa Daily" <arfa.daily@ntlworld.com>: Aug 12 01:57AM +0100 "Phil Allison" <pallison49@gmail.com> wrote in message news:526df419-3f56-43a6-9f50-a34321526fd1@googlegroups.com... > wiring away when it "trips" - cos its gets so damn hot.   > Be far better to slip a piece of silicone tube over the thing, as is often > done with NTCs.     Thinking about it, you're probably right about the reason for the sleeve. I'm sure I'll find something suitable.   >> primary short circuit for no good reason other than it felt like it ...   > ** You gotta hope the new one does not get that same feeling, or the other > one in the amp.     Yes, that's what bothers me. I never like high cost repairs to older items like this. It often seems to be the case that once they start failing, they just carry on with a different problem each time, just inside the 3 month warranty ...   > low voltages.   > Might be smart to get a quote for a replacement tranny made to suit that > Crown.   We got onto the people who handle Crown here today. They said that they didn't do spare parts, but they did have a transformer. £100 plus shipping plus tax. I suppose that's not a lot of money when you consider that it's a custom four-winding thing the size of a baby's head, but still a lot to shell out up front for a spare part. Considering the power output and replacement value of this amp, even if the final repair bill weighs in around the £200 mark, I suppose it has probably still got to be worth doing.   The customer has been given an estimate now by the shop, so we'll see what he decides in the next few days, I expect ...   Arfa

dplatt@coop.radagast.org (Dave Platt): Aug 11 10:57AM -0700 In article <bac45eb6-f681-4ec4-b774-274e88730824@googlegroups.com>,   >What if I'd remembered wrong? What if one of the kids moved the PC and bumped the balance knob?   >CRAPCRAPCRAPCRAPCRAP!!!!!!!!   >The balance knob was all the way to one side and when moved back to center, the Onkyo is fixed.   There was much rejoicing!   I recently had a bad scare with the FM service monitor that I had dragged down to our city's ARES/RACES ham shack. I'd been asked to run a full check on all of the UHF/VHF radios, and the service monitor wasn't "seeing" any signal on any frequency. When I switched it to "generate" mode, there was no output at all.   I thought the frequency synthesizer circuit had died, and resigned myself to hauling it home for a full investigation and repair.   Just as I was finishing the box-it-up process, I thought "Hmmm... one thing I ought to double-check..." and I turned it around and looked at the back panel.   Sure enough... the tiny little time-base switch was set to "external". The last time I had used it, I'd been feeding it a 10 MHz reference signal from my rubidium oscillator, and had forgotten to switch it back to its internal time-base when I was done.   Threw the switch to "internal", checked it again, and the synthesizer was working fine.   I gave myself a slap on the wrist for not resetting it to normal operation after the previous usage... and breathed a sigh of relief that I'd discovered the error before I went all the way home with it.

MJC <gravity@mjcoon.plus.com>: Aug 11 07:45PM +0100 In article <3mpp9c-ath.ln1@coop.radagast.org>, dplatt@coop.radagast.org says... > I gave myself a slap on the wrist for not resetting it to normal > operation after the previous usage... and breathed a sigh of relief > that I'd discovered the error before I went all the way home with it.   Now if there had been a sensible warning light on the front panel you might have noticed earlier...   Mike.

jurb6006@gmail.com: Aug 11 03:04PM -0700 >"The balance knob was all the way to one side and when moved back to center, >the Onkyo is fixed. "   I've seen worse. That just happened to me and I am a pro. I had a similar unit, in fact an Onkyo TX-2500 which is a bit older, has no digital/quartz lock thingie in it. It DID have a blown speaker fuse, blown by fatigue actually. I put that in and I got one channel. Oh shit. So I take the bottom off and stat checking. The silent channel has no input to the power amp board, I trace it back to the tone board and sure enough it is losing it there. I get all the way to the output end of it and I see the transistors are amplifying just fine, but is dropped across a resistor. OK, open resistor, right ? Nope, checks fine. Must be a short circuit.   Guess how balance controls work. They short out the audio ! (that is how the get max gain in the center position, except a few which use a dual pot) Open a window ! BRAIN FART !   >"I am not really an audiophile - I can tell the difference between good and >bad styluses, good and bad speakers, but never was able to tell much about the >amplifier. But the Onkyo is head and shoulders above the Pioneer. "   I suspect you of being a closet audiophile. Or maybe you are in denial. lol   Really, it doesn't take a ten grand system. It doesn't have to be 30 years old. You might want to browse around audiokarma. Some interesting reading not only about how stuff sounds different even with the same power and specs, but WHY. If you're inclined you'll probably find some interesting threads there. Lately there have been discussions about damping factor and what KIND of distortion different amps or other equipment has and how well you can hear this or that.

jurb6006@gmail.com: Aug 11 03:07PM -0700 > > Do you happen to have an STK0100 II and if so, how much ? I am already fitting one into a Fisher CA-800 that used to have 0080s in it. The one I got I know is NOS. It might be nice to do both at the same time because I have to do some things to the heatsink because the 0100 is bigger.   > I have (2) STK0080II and (2) STK0100II available.   > Dan   How much and how far are you from Cleveland, Ohio ? I'll have to see if the guy ants to spend the bucks as well. Hopefully you don't wnat so much for them we have to put the money in escrow. I have had good luck with people on Usenet so I wouldn't mind trusting and just sending you a postal money order. (they are not forged because there is an 800 number you can call to verify them) I don't have a Paypal account but I know someone who does if you have to be paid that way.

jurb6006@gmail.com: Aug 11 03:20PM -0700 >"There was much rejoicing! "   My cohort and I sometimes buy used scopes from this surplus place on the east side. (I know most people don't mention that but us old west siders do around here)   Got a couple of pretty good deals, not extremely great scopes but usable for audio and a few other tings. Anyway, then people don't really know scopes ad we found that some of them, THEY don't know how to get a trace on them. Like setting them to auto trigger, or free run if it has it. Picked up a nifty Tek 422 with the battery option. I intend to replace the batteries with more modern ones but I am sure I am going to have to build the charging circuit. I might see about an of the shelf solution or possibly get the circuitry from an old laptop. I would hav to probably cut part of the motherboard or something, if that is even possible, and then most likely regulate the 19 volts down to 12, pretty sure it is 12.   And we got a Tek 7834 that used to cost more than a house for like $24. That tone however has a slight HV regulation problem which I will eventually get to. the main worry about that is that it is a big HV divider resistor. but then modification is my middle name for a reason. There is almost always a ay, andf the other surplus place (slightly farther, they are on the west side of the next place)has kagillions of old resistors, probably of every value ever made. And I mean 100.1 meg, 100.2 meg, you know. OK, I am exaggerating, but not that much.

jurb6006@gmail.com: Aug 11 03:24PM -0700 >"Now if there had been a sensible warning light on the front panel you >might have noticed earlier... "   Things like that irk me. YEARS worth of Tek stuff with no power light. Some have a little window that opens to reveal a light colored piece of plastic. Ridiculous. Same with these older Wavetek generators. Muy biddy has a 103 and I have a 111, they also lack a power light.   Can't even tell if the thing is plugged in, and that is important sometimes, depending on how your bench is set up. If you are out in the field it is even worse.   Don't pick on our old equipment, at least it doesn't run Windows !

You received this digest because you're subscribed to updates for this group. You can change your settings on the group membership page. To unsubscribe from this group and stop receiving emails from it send an email to sci.electronics.repair+unsubscribe@googlegroups.com.