Products > Test Equipment
Test Equipment Anonymous (TEA) group therapy thread
mnementh:
--- Quote from: Cubdriver on May 28, 2022, 07:46:52 pm ---
--- Quote from: mnementh on May 28, 2022, 07:01:12 pm ---
damn you. damn you to... New Jersey. >:D
mnem
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You’re welcome. ;D ;D ;D -Pat
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On the Bench Tonight: INFINITY RS-3000 Driver Refurb
http://www.hifi-classic.net/review/infinity-rs3000-221.html
So all y'alls may remember that I got this far aboot a month ago; well, the surround kit from Springfield Speaker has been here for a while, so today they finally came back on the bench.
Getting the last little bits of old foam took a little more than IPA; the corner of a towel soaked in Goo Gone worked, and was then followed by another corner soaked with IPA to get that residue cleaned up.
Here I've propped up the cone with some felt rings and foam tube from my plastic junk drawer; I've applied the cement to the underside of the roll foam and gave it ~30 seconds to tack up.
When I apply the roll foam to the cone, I'll work from the bottom inside the gap as well as the top. This allows me to make certain the roll foam is centered exactly on the edge of the cone. Then I'll go all the way around the cone pinching the roll edge tight between thumb and forefinger of both hands.
I don't usually distort the cone this much when I'm working; it's easy to permanently crease or rip a paper cone doing this. But to show the the work and with the flexible polypropylene cone, for this pic I felt it was okay.
Here I'm getting ready to do the final assembly of the roll foam; the advertised bass resonance of this speaker is 55 Hz, so I'm going to set my old Protek Function Gen to do a sweep from ~30-80 Hz to make sure it passes through the free air resonance frequency of the driver while I'm centering the cone. I've set amplitude so I can clearly hear it when it gets up around the higher end of the sweep; this is applying ~1-2V P-p under load.
Before I actually glue things down, I'll do a reality check on the driver to make sure I actually can get the cone to center properly using the dynamic method. I do this by holding the roll foam like so to find center where the speaker has normal excursion without the VC rattling.
If I can't find the "sweet spot", or if I do find it and horizontal inspection shows the cone is cocked off at a angle, then I know the voice coil has suffered damage from over-excursion and will need to be repaired.
This requires cutting out and replacing the domed dust cap, which is something I try to avoid doing, as on modern speakers it can really affect the vocal range sound of the speaker.
Here I'm applying cement to the basket of the driver; I'll let it tack up for about 30 seconds before removing my felt and foam blocks and sticking the roll foam down in 4 spots based on how the sound reacts.
This is a very time-critical step; as soon as I have those 4 spots down, I will turn off the sweep gen and deliberately press on the cone unevenly in those same 4 quadrants to see if I can make it deflect and rub the voice coil. If I can, I'll lift the roll foam with curved tweezers and move it towards the side where rubbing does not occur; just a mm or two.
Once I get the foam situated so I cannot make the VC rub by pressing unevenly on the cone, or I if get it so it rubs with about the same deflection in all 4 quadrants, I'll turn the sweep generator back on while I finish stitching the glue down all the way around the basket.
And here the speaker is after the glue is stitched down all the way around. I've turned the amplitude up so I can hear the full 30-80 hz sweep clearly; this has the sweep generator producing ~15V p-p unladen across the entire sweep, with laden signal ~2.5V p-p to a max of ~6.7V p-p at its free-air resonance of ~39 Hz.
Here I've finished gluing down the gasket shims; next up will be the relatively boring part of doing cabinet rehab. I'm knackered, so we'll visit that tomorrow after all the cement has time to cure overnight. :=\
mnem
Cubdriver:
Nice writeup, mnem! Thanks.
-Pat
Neomys Sapiens:
--- Quote from: mansaxel on June 24, 2022, 10:48:15 pm ---5440 5B40 update:
U165 is toast. The trigger signal arrives, in-spec, to it, and does not depart. There's no blown tant on its supply; it has just below 5V on the supply pin, and it's not noisy. It does also draw some power.
Parts list sez:
--- Code: ---U165 155-0109-00 B010100 B021739 MICROCIRCUIT,LI:MONOLITHIC,TRIG 80009 155-0109-00
--- End code ---
So, a quick Ebay glance gives that it is not Unobtanium; there are a couple sellers on the bay who want around 25 money for one, plus transatlantic shipping. Stiff prices, them. Does anyone here sit on a few?
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Is that thing in all 5Bxx plugins? In that case I would have one - the plugin is destined to be used in TM500 anyway.
cyclin_al:
--- Quote from: GreyWoolfe on June 26, 2022, 02:39:41 am ---
--- Quote from: xrunner on June 25, 2022, 03:49:57 pm ---
--- Quote from: med6753 on June 25, 2022, 03:47:42 pm ---
--- Quote from: xrunner on June 25, 2022, 03:39:23 pm ---
--- Quote from: med6753 on June 25, 2022, 03:33:15 pm ---I don't know if USA ham licenses have to be renewed or not.
As I recall my 11 meter license was permanent. I still remember my call sign even though no one ever used them. KBHY5427. :D
--- End quote ---
Yes every ten years.
Gee, that must really stretch some of those Hobo's abilities. :P :-DD
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You have to get an FCC account and log in, figure out how to do what you need to do using the system of a massive bureaucracy ...
so yes you are right. :palm:
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Just went through the dance on the FCC universal licensing system to renew mine. You use the FRN number on your license as the user ID to create an account. Even though I have a current email on file, never did receive notification of renewal. Had to navigate the site again to find/download it. Med, my 11 meter license was KND3913.
EDIT: forgot to add that it was $35 USD to renew as I have a vanity call sign. I was licensed as KG4BOM, then became K9WLF and when I got my amateur extra license I became NW0LF as I wanted a 2X2 callsign-that is 2 letters, number and 2 letters that designate amateur extra.
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I quite like your callsigns!
My own experience with HAM licensing has been mixed positive and negative.
Industry Canada (what it was when I got licensed) HAM licenses are free for the first one, and there is a charge for additional licenses, $75CAD at the time I did my second IIRC. There are no renewals or regular fees.
These licenses do not indicate ratings or operating limitations. 2 letter callsigns (2 letters after the number) are highly desirable, and it depends on availability of the callsign and who gets their request done first.
I met my examiner at a public library, wrote the exam and filled in the paperwork for my new callsign VE3TSD. That was a nice availability, as car road rallies are often called TSD (Time, Speed, Distance) rallies.
The examiner was suitably dressed for a public servant, albeit with slightly disheveled hair.
At an upcoming road rally, my callsign had not yet been processed. My examiner was also at the event, and lent me one of his many extra ??? callsigns, to be used under his supervision. At the beginning of formal radio network operations, my instructor made an announcement to indicate my use of the callsign, that he was supervising me, and welcoming me to the community.
Not 5 minutes later, there is some other HAM on the air claiming to be a radio examiner, accusing me of stealing a callsign and not being a HAM.
Well , my examiner got on the air and succinctly quoted and explained the applicable rules. End of story?
This other HAM did not let up, and went on again about it.
My examiner got on the air again and uses a special VY9 callsign (government official; did not know he had that) and gave the other HAM an official cease and desist order! :o
Welcome to the community! That was supposed to be a fun car rally event!
I later met this other ham without indicating what callsign I had used; some middle aged guy with expensive clothes and car; definitely not a gentleman.
I later met my examiner at the car rally event; the most hobo of any hobo I hoped never to meet; yet this guy was a real gentleman. I have no idea how someone can transition from public servant to such hobo in such a short time!
Some years later, VA2/VE2 became the appropriate callsign to use. Since I liked what I already had, I paid the fee and got a second callsign. That kept me in good standing and I could meet the conditions to keep my first callsign. A guy I used to work with, also a HAM, started giving me a hard time about not having an appropriate callsign (based on my first). I told him simply I was compliant with the rules. He came back about it a week later. I told him to check the official database (where he could have found both listed). He came back about it a week later again. I had to explicitly tell him what my second callisgn was and asked him to go check how long I had it for. That finally shut him up. I am not sure how a license gives people the idea they can play police...
BU508A:
--- Quote from: Saskia on June 25, 2022, 08:44:33 pm ---while I was out cold, umm, with nasty fever, my new war instrument arrived.
--- End quote ---
"Onward brave warriors!"
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