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Search: Posts Made By: PeteS in CA
Forum: Troubleshooting Power Supplies and Power Supply Design 03-20-2019, 11:22 AM
Replies: 25
Views: 376
Posted By PeteS in CA
Re: Apple ][+ Astec power supply

I don't think they were fixed frequency. That said, they were normally above 20KHz, so they would not be audible, and bipolar transistors limited the practical maximum switch frequency to around...
Forum: Troubleshooting Power Supplies and Power Supply Design 03-19-2019, 12:50 PM
Replies: 25
Views: 376
Posted By PeteS in CA
Re: Apple ][+ Astec power supply

The main difference I've seen between a TO-3 and a TO-204 is that the former has a rounded top on the dome/cap. They were/are good for heat dissipation and better at mounting flush to a surface than...
Forum: Troubleshooting Power Supplies and Power Supply Design 03-18-2019, 06:27 PM
Replies: 25
Views: 376
Posted By PeteS in CA
Re: Apple ][+ Astec power supply

Ca. 1981 when I worked for Boschert we got ahold of an Apple ][+ P/S and I figured out the schematic (by staring at the PCB) and tested its performance. Astec hadn't done a very good job of removing...
Forum: Troubleshooting Power Supplies and Power Supply Design 03-15-2019, 05:26 PM
Replies: 25
Views: 376
Posted By PeteS in CA
Re: Apple ][+ Astec power supply

OMG, hilarious! I'd guess the vintage is ca. 1982, and I'm chuckling at the switch transistor with the part number removed. Astec used NEC TV horizontal flyback transistors.

That's a discontinuous...
Forum: General Electronics Technical Discussion 03-15-2019, 05:14 PM
Replies: 11
Views: 165
Posted By PeteS in CA
Re: Help finding a suitable replacement FCHS30A08

If you use a 40A or 60A part, the forward drop might be a little lower (50mV-100mV?). OTOH, if you use a 100V part instead of 80V the forward drop might be a little higher. In a high current dual...
Forum: General Capacitor Questions & Issues 03-11-2019, 02:29 PM
Replies: 7
Views: 161
Posted By PeteS in CA
Re: Bad caps on an M-audio DSM2 power supply

The stuff atop C31 looks like glue, possibly to stabilize the resistor that looks like it was added in parallel with another resistor. That glue apparently tends to get conductive as it ages and is...
Forum: Troubleshooting Power Supplies and Power Supply Design 03-08-2019, 06:15 PM
Replies: 15
Views: 269
Posted By PeteS in CA
Re: Help identity blown part in PC psu

Line-filter-free zone! Since it was built around March, 2006, I'm going to guess it might be a Power Integrations standby regulator, or maybe a 384x PWM.
Forum: General Capacitor Questions & Issues 03-07-2019, 02:39 PM
Replies: 20
Views: 311
Posted By PeteS in CA
Re: Replacing 8 Caps on motherboard and 2 on PSU - which ones are good replacements?

That power supply was probably built in August of 2003. So I'd suggest Nichicon PW, Nippon Chemi-Con LXZ, or Panasonic FC. Those are pretty much equivalents, so go with price and availability.
Forum: General Capacitor Questions & Issues 03-06-2019, 03:20 PM
Replies: 20
Views: 311
Posted By PeteS in CA
Re: Replacing 8 Caps on motherboard and 2 on PSU - which ones are good replacements?

The "pink thing" is a pre-load resistor. I think it's

Red - Green - Gold - Gold = 2.5 ohm, 5%

or

Violet - Green - Gold - Gold = 7.5 ohm, 5%

I think it might be a 2W or 3W resistor.
Forum: Troubleshooting Power Supplies and Power Supply Design 03-05-2019, 12:40 PM
Replies: 17
Views: 260
Posted By PeteS in CA
Re: Recapping Mean Well MWP-606

Regarding the YXGs, the date code format on the new parts looks correct to me, while the date code format on the old parts does not. Unless Rubycon changed their formatting in the past 10 years or so.
Forum: General Electronics Technical Discussion 02-25-2019, 11:27 AM
Replies: 22
Views: 197
Posted By PeteS in CA
Re: 555 pwm

The 555 timer is not a PWM IC, though it can be used that way. IIRC, Boschert's OL50 and OL65 model power supplies used a 555 timer. These were late 1970s design bipolar transistor-based continuous...
Forum: General Capacitor Questions & Issues 02-25-2019, 11:17 AM
Replies: 7
Views: 176
Posted By PeteS in CA
Re: Are these caps ok ?

Your pix are not well focused, but if you mean the reddish marks on the PCB, those are probably inspection marks (made by the inspector to show (s)he looked at that part).
Forum: General Capacitor Questions & Issues 02-25-2019, 11:13 AM
Replies: 1
Views: 68
Posted By PeteS in CA
Re: Best Replacement For Panasonic ECEP2HP152HA

Twist-lock types are closer to general purpose than are the many flavors of low impedance types. 85C rated parts especially. So I'd go for rated voltage and value. If the T-UP series has been...
Forum: Troubleshooting Power Supplies and Power Supply Design 02-22-2019, 11:41 AM
Replies: 5
Views: 123
Posted By PeteS in CA
Re: Help identifying power ic?

Either img tags are not working, or vBulletin is not recognizing the imgur page as an image, https://imgur.com/a/2oQ3LXE .

I can't see clearly any IC such as berthfield described, but there is an...
Forum: General Capacitor Questions & Issues 02-20-2019, 10:44 AM
Replies: 3
Views: 842
Posted By PeteS in CA
Forum: General Capacitor Questions & Issues 02-20-2019, 10:43 AM
Replies: 3
Views: 1,053
Posted By PeteS in CA
Re: Problem with LG LW40 Express

The OP is from 2010.
Forum: Troubleshooting Power Supplies and Power Supply Design 02-11-2019, 01:02 PM
Replies: 4
Views: 163
Posted By PeteS in CA
Re: Delta DPS-360FB A from Dell Studio XPS 435MT

Looks like that PSU is about 10 1/2 years old. Very decent life, though it'd probably still be OK had Nichicon PWs or HEs (or UCC LXZ or KYs) used instead of the Ltecs.

Companies like Dell and HP...
Forum: Troubleshooting Power Supplies and Power Supply Design 02-11-2019, 12:36 PM
Replies: 2
Views: 148
Posted By PeteS in CA
Re: Delta dps-300sb doesn,t start no output no led

In the 5VSB circuit? Or in the PWM circuit?
Forum: Troubleshooting Power Supplies and Power Supply Design 02-06-2019, 12:15 PM
Replies: 1,554
Views: 310,594
Posted By PeteS in CA
Re: the gutless, bloated, and fried power supply hall of shame

That "Duro" might be good for 200W: wimpy input bridge rectifiers; 330uF input lytics; lightweight heatsinks; small main output transformer; small output inductor. Somewhere around 200W-250W it would...
Forum: General Capacitor Questions & Issues 02-04-2019, 02:26 PM
Replies: 2
Views: 182
Posted By PeteS in CA
Re: Chemi-Con caught price fixing

Rubycon and others: https://www.justice.gov/opa/pr/three-companies-agree-plead-guilty-fixing-prices-electrolytic-capacitors

Also Nichicon:...
Forum: General Capacitor Questions & Issues 02-04-2019, 02:23 PM
Replies: 25
Views: 603
Posted By PeteS in CA
Re: Overvolting/reversing a polymer cap

Pretty sure it was hundreds of hours if not over a thousand. Not bad for 2000 hour (at max ripple and temp) parts. It was ~10 years and two jobs ago, so hazy memories.
Forum: Troubleshooting Power Supplies and Power Supply Design 02-01-2019, 03:53 PM
Replies: 3,013
Views: 733,996
Posted By PeteS in CA
Re: Power supply build quality pictorial. part 2

Well, the most recent date code I spotted in the pix was "9752", on the PCB. So this was built in early 1998. This is consistent with the .7A 5VSB rating.

I do remember a Delta PSU that was in...
Forum: Troubleshooting Power Supplies and Power Supply Design 02-01-2019, 03:29 PM
Replies: 1,554
Views: 310,594
Posted By PeteS in CA
Re: the gutless, bloated, and fried power supply hall of shame

That output inductor is extra crispy! Either it was badly overloaded for a long time or it was run so hot the core lost its magnetic characteristics and self-fried. Or both.

Those input rectifiers...
Forum: General Capacitor Questions & Issues 02-01-2019, 03:17 PM
Replies: 25
Views: 603
Posted By PeteS in CA
Re: Overvolting/reversing a polymer cap

It's been 10 years or so, but I think that when I tortured some polymer caps - 8X or 10X their ripple current rating - they just deteriorated slowly. I probably declared victory when they reached 2X...
Forum: Troubleshooting Power Supplies and Power Supply Design 01-30-2019, 11:56 AM
Replies: 11
Views: 210
Posted By PeteS in CA
Re: Delta ADP-310AF No Power and frequently chirping

Sounds like one of those caps has gone high ESR. It charges enough to let the PWM start, but can't provide enough voltage for the PWM to keep operating.
Showing results 1 to 25 of 500

 
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