Yes, photos. I didn't think Fairchild made 2sa1943/2sc5200 but a quicl google search tells me they are called KSA1943/KSC5200. The "K" in Fairchild parts indicates (I think) that they are made in Korea at a facility that was formerly Samsung. I could not find them listed with a single North American distributor and even www.fairchildsemi.com has very little info. The google search suggests they are available mainly in Asia.
So who sent you a set?
So who sent you a set?
God these fakers can really **** one off, my amp most likely uses Sanken 2SC3856 and 2SA1492. I do have spares of these gotten from a yamaha rx-v592 ht receiver that died on me, but the Q is if the power transistors are fakes. I have already repaired a marantz amp with a power transistor from the yamaha, 2SC4466 and 2SA1693, also Sanken devices. I never opened the original device from the marantz so i don´t know if it was genuine or fake bur probobly it was fake as it died during a off period while i was measuring inside the amp, got DC out when i turned the amp on again. Next time a power device in the marantz fail i´ll crack it open.
These devices i have mentioned here now are obsolete since 1990 or so huh ? Receiver were 12 years old when it died with a bang while i were connecting a poweramp to the sub out.
These devices i have mentioned here now are obsolete since 1990 or so huh ? Receiver were 12 years old when it died with a bang while i were connecting a poweramp to the sub out.
Hi all,
A quick update.
The Fairchilds have been running well since I wrote in last, which must be a few months now, and the Phonic 740 has performed pefectly. When I tested it, I used a dummy load and ran it to a good 100W+ without any problems whatsoever.
As for pictures, I'll have to take the unit apart again but not this week as I've got a gig next Friday and Saturday and I'm sure if I open it up I'm bound to break something!!!
Bob 😎
Forgot to mention I got them from a distributor in the UK and got the device spec sheets from Fairchild's website.
Try this
http://www.chipdocs.com/pndecoder/datasheets/FAIR/KSC5200.html
The link on Fairchild's site has been removed??
A quick update.
The Fairchilds have been running well since I wrote in last, which must be a few months now, and the Phonic 740 has performed pefectly. When I tested it, I used a dummy load and ran it to a good 100W+ without any problems whatsoever.
As for pictures, I'll have to take the unit apart again but not this week as I've got a gig next Friday and Saturday and I'm sure if I open it up I'm bound to break something!!!
Bob 😎
Forgot to mention I got them from a distributor in the UK and got the device spec sheets from Fairchild's website.
Try this
http://www.chipdocs.com/pndecoder/datasheets/FAIR/KSC5200.html
The link on Fairchild's site has been removed??
You guys will love this one. Every datasheet I've ever seen included curves for the device. 
I'll attach a couple of PDFs for the 2SA1302 and 2SC3281 that have no curves!
Use your own judgment, as the sheets were downloaded from www.datasheetarchive.com.
I'll attach a couple of PDFs for the 2SA1302 and 2SC3281 that have no curves! Use your own judgment, as the sheets were downloaded from www.datasheetarchive.com.
I don't mean the following as an accusation (since I have no facts) but as an observation and caution:
The fakes are presumed by many to originate is SE Asia. Thus an HK company I've never heard of publishing somewhat odd datasheets for out of production device may cause a raised eyebrow.
The fakes are presumed by many to originate is SE Asia. Thus an HK company I've never heard of publishing somewhat odd datasheets for out of production device may cause a raised eyebrow.
I found this test circuit on the web for pre-testing transistors to see if there counterfit.
It works well, all mine passed.
The text is in spanish, and as far as i can translate it, it says that the lamp should remain completly off until you press the switch. if the lamp comes on, the device has fail and is probably a fake.
Zc
It works well, all mine passed.
The text is in spanish, and as far as i can translate it, it says that the lamp should remain completly off until you press the switch. if the lamp comes on, the device has fail and is probably a fake.
Zc
Attachments
I suspect if it was a fake hitting the switch would probably destroy it anyway. Mind you, better blown up in the test rig than in the amp I suppose.
Bob 😎
Bob 😎
I have no information other that whats there. But. I used a small heatsink off an old pentium CPU with a weight on top to hold the device there. i held the switch for a good 20-30 seconds and the device never even got warm. I suspect that you could get away without a heatsink as if the device is going to fail. i suspect it would do so immediatly!
I need to do some more testing. the rig i built wasnt very easy to use. i plan on making a new one with a flip lever to hold the device down and a plug in socket etc.
I would imagine this cicuit would be good for testing a variety of devices in the 200 volt range. just change the bulb for different current ratings.
Us a 40 watt bulb for 50-60 watt devices etc. and if you used a variac and put a meter on it, you could test about anything!
The question i have is, if a 120V 100 watt light bulb draws in fact 100 watts at 120V. If you rectify the AC to DC you get about 170V in my math is correct. how much current is the bulb drawing then?? (i just havent put my meter to it yet)
AND, if a C5200/1943 are 230V 150 watt devices, how heavily can we load them ?? could i actually put a 150 watt bulb in there?
Zc
I need to do some more testing. the rig i built wasnt very easy to use. i plan on making a new one with a flip lever to hold the device down and a plug in socket etc.
I would imagine this cicuit would be good for testing a variety of devices in the 200 volt range. just change the bulb for different current ratings.
Us a 40 watt bulb for 50-60 watt devices etc. and if you used a variac and put a meter on it, you could test about anything!
The question i have is, if a 120V 100 watt light bulb draws in fact 100 watts at 120V. If you rectify the AC to DC you get about 170V in my math is correct. how much current is the bulb drawing then?? (i just havent put my meter to it yet)
AND, if a C5200/1943 are 230V 150 watt devices, how heavily can we load them ?? could i actually put a 150 watt bulb in there?
Zc
You misunderstand power ratings/the circuit. A 120W bulb will simply have lower resistance than a 100W bulb. Neither will draw their full power without being supplied their rated voltage. The power rating is probably nothing at all to do with the transistor power rating, it's just been found to have the right characteristics to offer some protection.
right, my point was to put a varic on it to vary the voltage to what ever working voltage you intend to use, or that the device is rated for. then switch out various bulbs to get what ever current draw you want to simulate a load etc.
Zc
Zc
The light bulb is actually supplied with AC
The transistor is exposed to rectified AC and works as a switch
This arrangements only tests the blocking capability of the transistor [1.4142 * mains voltage] and the non-repetitive pulse SOA at turn-on and turn-off
The transistor is exposed to rectified AC and works as a switch
This arrangements only tests the blocking capability of the transistor [1.4142 * mains voltage] and the non-repetitive pulse SOA at turn-on and turn-off
Eva said:
Oh yeah DUH, i knew that!! i just wasnt thinking about how it was actually wired! jeeze somedays my head just isnt connected! hahahah
ZC
K-amps said:
Ok, i played with this a bit more today after i purchased some 100W bulbs.
The Transistor does get warm/hot if you hold the switch on for 10 seconds or longer. It got hot enough that i let go of the transistor after about 10 seconds. So i am using a heatsink now.
I tried everything i could to blow up a C5200 today. I have one left that survived the last time the amp blew up so im using it at my test horse.
I filpped the power on/off, i repatedly press the switch, i raised the voltage up to about 130VAC, i lowered it down to about 30VAC and i varied it in between filpping on and off the power as i rotated the variac knob etc etc etc. and the transistor survived!
I hold the switch down for at least 60 seconds and im quite sure i could have just left it on all day.
So the circuit works pretty well. Now i wish i had some know fake devices on hand to see if the circuit will really test for them or if they will survive.
Zc
Some more fakes
I bought a 2SC3281, 2SC5200 and 2SA1302 from the market at very low prices.
The 2SC3281 printing was faint and looked like a poor laser etched text. The 5200 and 1302 devices had a shiny clear rectangle in the middle of the device inside which the numbers were apparently etched - very neatly.
The 2SC3281's text is not visible in the picture. The first 3281 is a genuine device. the 5200 and 1302 seem to be fakes.
The tests read:
2SC3281 ( genuine) Cbc = 1527pF, Cbe=8097 pF, Hfe 101 at about 450mA.
New 3281 ( number not visible) 1185pf, 7500pF , 87.
2SC5200 was 300pF, 854pF, 75.
2SA1302 was 33pF, 228pF , 38.
I rigged up a simple Hfe measuring device which can measure Hfe at higher currents than most (hfe measuring) DMM's.
Cheers.
I bought a 2SC3281, 2SC5200 and 2SA1302 from the market at very low prices.
The 2SC3281 printing was faint and looked like a poor laser etched text. The 5200 and 1302 devices had a shiny clear rectangle in the middle of the device inside which the numbers were apparently etched - very neatly.
The 2SC3281's text is not visible in the picture. The first 3281 is a genuine device. the 5200 and 1302 seem to be fakes.
The tests read:
2SC3281 ( genuine) Cbc = 1527pF, Cbe=8097 pF, Hfe 101 at about 450mA.
New 3281 ( number not visible) 1185pf, 7500pF , 87.
2SC5200 was 300pF, 854pF, 75.
2SA1302 was 33pF, 228pF , 38.
I rigged up a simple Hfe measuring device which can measure Hfe at higher currents than most (hfe measuring) DMM's.
Cheers.
Attachments
The hfe tester
The hfe tester is basically a current source providing the base current . The collectror current can be measured by putting a current meter in series with the power supply or measuring it in volts across a 1 ohm resistor ( as shown ).
Both positive and negative current sources are in parallel . The supply is switched between + or - 5 volts . The push button turns on the base current. The red led is the indicator for current flow for +ve current and yellow LED for the -ve . Not really required. The large switch is to toggle between +/- 5 volts for npn and pnp devices.
I made many errors on the pcb and so a few capacitors are on the rear side of the pcb and the board was meant to be connected to a pot to enable one to set a desired base current.
Will fix that on the next(?) pcb.
Cheers.
The hfe tester is basically a current source providing the base current . The collectror current can be measured by putting a current meter in series with the power supply or measuring it in volts across a 1 ohm resistor ( as shown ).
Both positive and negative current sources are in parallel . The supply is switched between + or - 5 volts . The push button turns on the base current. The red led is the indicator for current flow for +ve current and yellow LED for the -ve . Not really required. The large switch is to toggle between +/- 5 volts for npn and pnp devices.
I made many errors on the pcb and so a few capacitors are on the rear side of the pcb and the board was meant to be connected to a pot to enable one to set a desired base current.
Will fix that on the next(?) pcb.
Cheers.
Attachments
Isnt it time for a thread that lists all the low price amplifiers that had the original nice number Toshiba's ?
I can imagine a lot of people interested in wrenching those devices from old amplifiers.
I can imagine a lot of people interested in wrenching those devices from old amplifiers.
re. fake transistor
I bought the power transistors Toshiba 2sc5200 and 2sa1943 from the local part shop recently. I cannot find any thing abnormal about the appearance of these device. After installing those trans, the Amp just work fine. I increased the volume to quite a high volume, it did not fail, but the sound quality was very poor with lots of distortion, the sound was not blending well. The original ones just work fine in this condition.
I have the same problem with the pair 2sb688-2sd718. The problem in these pair seem worse. They produce too much heat which is abnormal. But none of them died.
I have met the same story with the driver trans Toshiba 2sa1930-2sc5198 and mje340-mje350. I replace these trans in a normal amp. The sound quality decrease considerably. ( those devices are comletely compatible)
I have broken some of the trans to see the internal silicon arrangement. It look just fine compared to those pics of orininal trans on our forum.
How's that? any body can help me solve this. Thanks inadvance.
I bought the power transistors Toshiba 2sc5200 and 2sa1943 from the local part shop recently. I cannot find any thing abnormal about the appearance of these device. After installing those trans, the Amp just work fine. I increased the volume to quite a high volume, it did not fail, but the sound quality was very poor with lots of distortion, the sound was not blending well. The original ones just work fine in this condition.
I have the same problem with the pair 2sb688-2sd718. The problem in these pair seem worse. They produce too much heat which is abnormal. But none of them died.
I have met the same story with the driver trans Toshiba 2sa1930-2sc5198 and mje340-mje350. I replace these trans in a normal amp. The sound quality decrease considerably. ( those devices are comletely compatible)
I have broken some of the trans to see the internal silicon arrangement. It look just fine compared to those pics of orininal trans on our forum.
How's that? any body can help me solve this. Thanks inadvance.
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