Happy to know they are still around.
Found it funny that they are yet another Company which still prominently states their FAX number, proof they still regularly use it.
Although that fact seems to ruffle some feathers here and there.
Found it funny that they are yet another Company which still prominently states their FAX number, proof they still regularly use it.
Although that fact seems to ruffle some feathers here and there.
They deal in parts for 60+ year old military systems like the B-52. Some of those mil-spec contracts were painfully translated from telegram to TELEX to FAX for authority. Dropping the FAX might lose contracts.
I was running to the UPS Store to get FAX in and out in 2009 to buy this house. I had a FAX but the phone was not hooked up yet. Yes, a more recent hi-finance was all e-mail and e-signatures.
Same here, but now my FAX machine has been collecting dust (not sure it will even turn-on) for some 10-15 years
And the last few times I sent one, I used one of those fancy WinFax Modems, which, get it, use no paper!!! 😱
Oh, a couple times when I needed to scan something in a jiffy, such as a hand drawn schematic, etc. I Faxed it to my own PC.
Fuzzy 2 bit 200DPI quality but better than nothing.
No the SDF8101 isn’t even close. It’s a small signal mosfet. 8101 looks like a date code. If I had to venture a guess it’s 60 volts 20 amps - and “16” is the hFE range. Other makers from the way back machine like Tesla, Kest, etc had similar numbering schemes. House numbering for Crown and Peavey back in the day was the same way - current, voltage and gain were encoded into the part numbers. It wasn’t immediately obvious and you needed their decoder rings but that’s all it was.
$22 a pop from Surplus Sales is a bit steep, considering the possibility it might not work. But then again standard products are all that high these days - what a difference a year makes. I’d gamble $3-5 each easy. Just a few short years ago pre-pandemic I had several surplus houses I used regularly and occasionally I found good high current house numbered parts that would likely work. For a song. Everybody’s closed up shop now.
$22 a pop from Surplus Sales is a bit steep, considering the possibility it might not work. But then again standard products are all that high these days - what a difference a year makes. I’d gamble $3-5 each easy. Just a few short years ago pre-pandemic I had several surplus houses I used regularly and occasionally I found good high current house numbered parts that would likely work. For a song. Everybody’s closed up shop now.
Hi, I decided to order a couple replacements at 22 bucks a pop plus shipping I will either be a happy owner of a working power supply.... or there went 50 bucks up in smoke... Happy New Year FIREWORKS is all this one might be. Ahhhhh.... I will do a good job of INSPECTION and if I find any DEVIANTS I will look further. I understand there should be a certain parity of readings throughout the circuitry so I look for that, a happy readings place. I had a fall and broke my back recently so I had to power through it for a week befor ER xrays etc showed a compression fracture... OUCH... but no surgery needed.... Just a month of bed rest and drugs and ugggggggggg............. Happy NEW year here... Till then... Cant wait for 2022 to end. Keep yas POSTED!....
Oh yes, I decided to go the EXPENSIVE/REPLACEMENT route vs the CROSS REFERENCE a NEWER replacement from modern stock BECAUSE of the great discussion and INPUT here. It APPEARS these are 60 AMP capable... The amplifier LITERATURE states a "300 watt PWM regulated switching power supply for full rated output down to 20hz, both channels driven." BUT further on in the literature it reads "A pair of 100 AMP high speed switching transistors maintain the high efficiency and reliability of the power supply...
SO... My goodness. I have YET been able to locate a SPEC sheet for these antiques. LOL. BUT as I mentioned earlier, theres a place in Nebraska that sells em, old stock, so I purchased a couple. These COULD be "20 amp".... or "60 amp"..... OR "100 amp" transistors... LOL. I am THINKING they are 60 amp EACH with a combined output of 100 amps with a +/-20 amp headroom for operating safety etc.
Will see soon... in the mail. Should I change the associated capacitors?.... the ELNAS and them two NICHICONS.... Hmmmmm I CHECK them with METER and they are in SPEC..... I will keep yas posted. HAPPY HOLIDAYS and THANKS! DIY Audio gang... BDBD/2022
The headroom is because beta falls off at high current. They may be capable of 100A peak, but if they take 20 amps of base current to do it that has to be supplied by the feedback winding on the inverter transformer. That reduces efficiency. Especially when lightly loaded since the base current is forced. At 20 amps they likely have full gain, requiring only a couple hundred mA to drive. You can live with that constant drain on the battery (The chip-amp in the head unit probably draws that much).
If the caps measure good you can leave them, but they are not a cost driver. Little ones in the signal path are actually more at risk of going out, since they may not have enough DC bias on them to keep them “formed” properly over years/decades.
If the caps measure good you can leave them, but they are not a cost driver. Little ones in the signal path are actually more at risk of going out, since they may not have enough DC bias on them to keep them “formed” properly over years/decades.
Thank You for chiming in, DC offset promotes reforming. Good to know. Smaller caps might be a possible candidate for replacement in that regard. I will recheck them before I reinstall the amp in my car. I installed the "NEW" Power source transistors I got in the mail today. I used the one that survived and a new one that had a closer number set upon measuring them. So yes they are working now. 29 volts +/- and 12 volts and ground all work now. The amp sounds good and both channels seem fine now. I will run it for 24 hours and see how that goes, I will blast it loudly.... I HOPE thats it for this problem prone amp. THANKS to you all.... BDBD/2022
Got the transistors in the mail today and my amp is back and working again. For how long... time will tell. Run it for 24 hours again to see.... Run it HARD too.... Uggggg.... Better work this time and NOT blow a fuse. Thanks all!!! BDBD/2022
Just noticed that 0R33 carb comp emitter (?) resistor R25 on one of your amplifier boards that obviously has become too hot in the past. You may need to check why.
Best regards!
Best regards!
Post #1 said the power transistors in the amp itself were blown at one time. Hopefully that problem has long since been corrected. If the amp modules run properly without overheating it probably is (unless you end up with fake transistors in it, then anything goes).
would that be the LEFT or RIGHT board you are looking at. And yes, I ran this amp for well over 10 hours on my bench at low volumes... seemed happy... played LOUD. So I decided to pop it back inmy car and run it hard for a song... Made it to the end of the song then POP.... There went 50 bucks again... This amp.... I tell ya. It hardly even got warm. blew a 30 amp fuse. GREAT. I need a REAL TECH that can work on 45 year old amplifiers to give this amp a once over.... It's got issues for sure when ya turn up the volume... Ugggggg back to the drawing board. THANKS!!! BDBD/2022
Oh well.... it ran at low volume for several hours so I decided again to see.... It ran for a song then POP... blew a fuse again. This amp works fine at low volumes it seems BUT once ya get to cranking it up it dies pretty quickly. Yet another transistor I fear is dead... great. Anybody here do MAIL ORDER REPAIRS of 45 year old car amplifiers?... NO IC chips in this amp at all. OLD SCHOOL. Any help will be greatly appreciated.... I am NOT the person who will bring this amp back to life it appears... Ugggg So complicated. My aching back. THANKS ALL!!!! HAPPY MERRY!!!! BDBD/2022
Couldn't you have acquired a brand new amp for all the money you squandered into this damned old one? It's just a car amplifier, mind you 🙄...
Best regards!
Best regards!
well my friend... I have installed thousands of sound systems into customers cars in the 5 decades I been messing around with car audio. I have MANY amplifiers that can easily replace this one. No problem. BUT This is MY car and MY sound system and that being said I will more than happily go through whatever HALLUCINATIONS I MUST go through to FINALLY get my system back to proper operating condition. Heres the story thus far..... I PULLED the amp cause it popped its 30 amp main fuse so I thought it was TOAST again BUT..... Upon examination all the transistors read ok... Hmmmmmm..... SO I reassembled the amp and I have it hooked up to my BENCH now... working OK.... Plays LOUD and has yet NOT tripped the 10 amp circuit breaker. TIRED of popping expensive 10 amp fuses so I use a circuit breaker. Its RUNNING again now... Plays LOUD. My goodness. Ya might GET that when this amp enters my CAR... it runs HARD.... Something bad happens and POP... I am wondering if the transformer which is ENCASED in STEEL.... might have overheated and so its OK cold.... but when HOT it shorts... Power supply Transistor blew once already as well as 2 AMPLIFIER main transistors. I managed to find replacements online. Thus far its running on my bench. UGGGGGGGGGGGGG..... BDBD 2022
OK...... I PULLED the amp cause it popped its 30 amp main fuse so I thought it was TOAST again BUT..... Upon examination all the transistors read ok... Hmmmmmm..... SO I reassembled the amp and I have it hooked up to my BENCH now... working OK.... Plays LOUD and has yet NOT tripped the 10 amp circuit breaker. TIRED of popping expensive 10 amp fuses so I use a circuit breaker. Its RUNNING again now... Plays LOUD. My goodness. Ya might GET that when this amp enters my CAR... it runs HARD.... Something bad happens and POP... I am wondering if the transformer which is ENCASED in STEEL.... might have overheated and so its OK cold.... but when HOT it shorts... Power supply Transistor blew once already as well as 2 AMPLIFIER main transistors. I managed to find replacements online. Thus far its running on my bench. UGGGGGGGGGGGGG..... fun fun fun...
BDBD 2022
BDBD 2022
Hi, it was warm at best when a song ended it popped the fuse so thermal.... Oscillation is a foreign language for ol me at this point so as I mentioned I wont be the one to get these working again it appears. I need to search for someone who remembers AUDIOMOBILE gear as i do not have any schematics etc. GURU.... I need a Guru. THANKS!!!
So it works properly on a bench power supply, but on a car battery it blows fuses?
You need to figure out whether it is the power supply or the amp board that is misbehaving. Will the power supply run properly on say, 15 volts? Does the supply itself run properly at low load, then do stupid things at heavier load? Do the amp boards misbehave if run off a +/-29 volt supply (using a transformer, running off standard plug in power)?
You need to figure out whether it is the power supply or the amp board that is misbehaving. Will the power supply run properly on say, 15 volts? Does the supply itself run properly at low load, then do stupid things at heavier load? Do the amp boards misbehave if run off a +/-29 volt supply (using a transformer, running off standard plug in power)?