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Search: Posts Made By: eccerr0r
Forum: General Electronics Technical Discussion Today, 10:02 AM
Replies: 104
Views: 1,076
Posted By eccerr0r
Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

We'll see how long it lasts and if it goes up in smoke. I don't know what protection this thing really has.

7.5 minutes is ⅛ hour, which is an immense load. 1.5Ah / ⅛h = 12A (in the "new"...
Forum: General Electronics Technical Discussion Today, 04:12 AM
Replies: 104
Views: 1,076
Posted By eccerr0r
Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

The battery appears to be wrapped and no real good markings visible on it. I suspect it should be just as good as both vacuums have similar runtimes (~7.5 minutes) and initial battery capacities...
Forum: General Electronics Technical Discussion Yesterday, 07:47 PM
Replies: 104
Views: 1,076
Posted By eccerr0r
Re: Directly replacing NiMh cells with Li-Ion cells - bad idea ?

Well, I picked up another junk handheld vacuum cleaner for a buck. I grabbed it because it seems to still be spinning, and said "lithium 3.6V" ... Jackpot, it might actually match the specifications...
Forum: Troubleshooting TVs and Video Sources Yesterday, 09:08 AM
Replies: 6
Views: 105
Posted By eccerr0r
Re: CRT TV:What causes this kind of geometry issue?

There are a lot of strange controls needed to control a flat screen short neck CRT versus a traditional long neck curved screen.

/_/ and \_\ parallelogram control
/_\ and \_/ trapezoid control...
Forum: Troubleshooting Power Supplies and Power Supply Design Yesterday, 09:00 AM
Replies: 27
Views: 198
Posted By eccerr0r
Re: Voltage Regulators and Heat Issues

Yes, all switch mode power supplies use some sort of PWM to regulate.
Forum: Troubleshooting TVs and Video Sources 03-20-2019, 10:06 PM
Replies: 6
Views: 105
Posted By eccerr0r
Re: CRT TV:What causes this kind of geometry issue?

:lolsign:

Well with flat CRT screens a lot of magic is needed to make sure that things are lined up. A lot of the times a microcontroller has a setting to control parallelogram alignment and a...
Forum: Troubleshooting Power Supplies and Power Supply Design 03-20-2019, 07:17 PM
Replies: 27
Views: 198
Posted By eccerr0r
Re: Voltage Regulators and Heat Issues

It's surprising how loud these piezo buzzers can get... The flaky one I have is only a about 1cm in diameter.

I have another piezo buzzer from an expired CO alarm with a 4cm piezo element. This...
Forum: Troubleshooting Power Supplies and Power Supply Design 03-20-2019, 03:46 PM
Replies: 27
Views: 198
Posted By eccerr0r
Re: Voltage Regulators and Heat Issues

That changes things now does it...

I was playing with one of my piezo buzzers with built in oscillator and it was quite flaky, probably because it's cracked. But it was modulating kind of funny...
Forum: Troubleshooting Game Consoles & Other Weird Devices 03-20-2019, 01:43 PM
Replies: 32
Views: 2,593
Posted By eccerr0r
Re: Post your worthless and/or pointless repairs

Nice grats... I was wondering who uses pencils anymore (does anyone handwrite anymore?)... :o:

I have a problematic shaded pole motor like the one you have, and I suspect that the rotor's "rungs"...
Forum: Troubleshooting Power Supplies and Power Supply Design 03-20-2019, 01:26 PM
Replies: 27
Views: 198
Posted By eccerr0r
Re: Voltage Regulators and Heat Issues

Are you sure they are transducers or are they buzzers? Will they beep with just DC connected to them? Now I'm confused again...
Forum: Troubleshooting Power Supplies and Power Supply Design 03-20-2019, 12:23 PM
Replies: 27
Views: 198
Posted By eccerr0r
Re: Voltage Regulators and Heat Issues

The inductor is the same principle as a boost switch mode power supply, except we don't care about which way the current goes (so the diode isn't needed except perhaps to protect the transistor), AC...
Forum: Troubleshooting Power Supplies and Power Supply Design 03-20-2019, 11:45 AM
Replies: 27
Views: 198
Posted By eccerr0r
Re: Voltage Regulators and Heat Issues

If you're concerned about power loss as heat, yes you need a switching regulator which is designed for efficiency. The modules with inductors preassembled suggested by redwire and R_J above are your...
Forum: Troubleshooting Power Supplies and Power Supply Design 03-20-2019, 08:54 AM
Replies: 27
Views: 198
Posted By eccerr0r
Re: Voltage Regulators and Heat Issues

Add other dissipation devices before the 7805 (resistors, preregulators). You could use a 7818, then a 7812, then the 7805, and the heat is distributed among the three.

Else use a switching...
Forum: Troubleshooting Power Supplies and Power Supply Design 03-20-2019, 01:44 AM
Replies: 25
Views: 361
Posted By eccerr0r
Re: Apple ][+ Astec power supply

Too many burst RIFAs. Why haven't I seen any dead WIMAs...

Incidentally the BUW44 probably could work as a replacement for the PSU, it should switch at 200KHz, sustains 400V, 6A... This 200KHz is...
Forum: Troubleshooting Power Supplies and Power Supply Design 03-19-2019, 06:01 PM
Replies: 25
Views: 361
Posted By eccerr0r
Re: Apple ][+ Astec power supply

The reasons why I think 1973 is because:
1. Germanium power transistors have not been made for decades.
2. Bendix has been gone for decades.
3. I think 1963 is a bit too old for the transistor,...
Forum: Troubleshooting Power Supplies and Power Supply Design 03-19-2019, 05:29 PM
Replies: 25
Views: 361
Posted By eccerr0r
Re: Apple ][+ Astec power supply

Hah... None of these TO-3/TO-204s were made this century!

As far as I know of the pictured transistors:
BUW44: made in 1980
2N3055: made in 1976
2N1136A: made in 1973 (as far as I can guess)...
Forum: Troubleshooting Power Supplies and Power Supply Design 03-19-2019, 04:09 PM
Replies: 25
Views: 361
Posted By eccerr0r
Re: Apple ][+ Astec power supply

Anyone got pictures of a french fried or bloated X/Y cap (certified by UL or whatever safety agency in your locale) that's not a Rifa? :D

I have yet to see one, and still feel convinced the old...
Forum: Troubleshooting Power Supplies and Power Supply Design 03-19-2019, 12:27 PM
Replies: 25
Views: 361
Posted By eccerr0r
Re: Apple ][+ Astec power supply

TO-3/TO-204 (why did they change the designation? Or is it it because of the flat flange vs textured, aluminum vs steel, or low profile vs full height?) is "rare" now in modern design because...
Forum: General Electronics Technical Discussion 03-18-2019, 02:14 PM
Replies: 9
Views: 156
Posted By eccerr0r
Re: Failed RF power transistors...DC testing (i.e. with multimeter)?

Yeah, that's the problem. It's an old single band mobile radio. I don't think the radio goes much for ebay prices (probably 30 USD at most, and shipping kills the deal) hence the hesitance on...
Forum: General Electronics Technical Discussion 03-16-2019, 04:00 PM
Replies: 9
Views: 156
Posted By eccerr0r
Re: Failed RF power transistors...DC testing (i.e. with multimeter)?

Thanks, yeah I guess that's what I was wondering, "short or open with not much in between". Yes it's a goldwing ceramic. But weird I did seem to get the characteristic C-B and B-E 0.7V drops of...
Forum: General Electronics Technical Discussion 03-16-2019, 08:32 AM
Replies: 9
Views: 156
Posted By eccerr0r
Re: Failed RF power transistors...DC testing (i.e. with multimeter)?

The hFE/beta tester is also done at DC which I wonder if it's sufficient...

Using diode check in-situ, it seems okay, but I dread taking this device out of circuit however... going to be painful...
Forum: General Electronics Technical Discussion 03-15-2019, 07:16 PM
Replies: 9
Views: 156
Posted By eccerr0r
Failed RF power transistors...DC testing (i.e. with multimeter)?

When a RF power transistor fails, is it still possible to test it at DC? Do they tend to typically fail in a way such that you can't detect at DC (unlike the fact most power switching transistors...
Forum: General Electronics Technical Discussion 03-13-2019, 10:26 AM
Replies: 14
Views: 197
Posted By eccerr0r
Re: Air Supply Systems

The question is: what are you using air and vacuum for? Hopefully not cleaning?

Note that not only you need to oil these compressors, the air needs to be clean else you're going to destroy the...
Forum: General Electronics Technical Discussion 03-11-2019, 11:04 PM
Replies: 3
Views: 93
Posted By eccerr0r
Re: Electronic Fence

The main reason for not inflicting death is if it dies on the electric fence, it will short, and now the fence no longer is active against other animals trying to get across...

Those tesla coils...
Forum: General Electronics Technical Discussion 03-08-2019, 04:29 PM
Replies: 15
Views: 213
Posted By eccerr0r
Re: Dead car battery and alternator strain?

No, they cannot add alcohol to depress the freezing point. Water is part of the reaction when charging, all that water needs to be there to let the sulfuric acid to go around (not to mention...
Showing results 1 to 25 of 500

 
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