Dude you are the greatest ! I would have been scared to death damn near to go anywhere near that amplifier with a pointed probe like that ! You got the job done !
I had my HR-752 and TFM-35 rebuilt by a fella in Oregon. I'm so glad I did. Added a decent set of speakers, and it sounds as good or better than most receivers you can easily dump $1,000+.
I have had Bob Carver amps, speakers, subs, tube cd players and so on for 35 years. NO ONE would EVER fix the very few things that went wrong, I shorted a channel on an amp by drilling through speaker cable. Everyone said that Carver amps are CRAZY and they will not touch them. Well I have 40 year old amps still going strong, I'll take crazy any day, Thanks for the video, it shows how tough they are to work on, Bob Carver, Mad Scientist
Follow the service manual, it´s very easy to fry the transformer as the power lines will switch rapidly when poking in the signal level like that, if the triac blows or is short. Lock the supply line level when working like that. You do not need full line voltage untill everything is in order for load test.
Nice work! Those Carver amps really pack a punch. The peak ESR meters arent supposed to be fussy about correct polarity, so those readings were probably correct
VERY good job, congratulations! A cheap infrared thermometer would be useful to check the temp. in the output transistors. A friend give to me a Carver PM-1200. It's a creepy beast, can blow any "home" speaker in a blink of an eye. It was given away because it is on 110V, i have to convert it to 220 (Local mains here). There is a service note to do that, but it is VERY risky business with all those high DC voltages.
One thing to be careful of is those D555 transistors that looked like the label was scraped off and reprinted have a high probability of being counterfeit transistors. I have seen them and they do not tend to last. Any transistor that has the mark altered or indication of sanding throws up red flags.
Yeah they maybe a pain to work on but IMO those are cool designs. If you look at how the air system works on those amps its one of the most cleaver designs for cooling on a rack mount type amp ive seen. I actually like its design.
@@Farmradio , it has a "silent" switch which slows the fan down, but when the switch is off, fan runs normal speed, when power to unit is switched on with no load.
I have one of these that still works. Be careful about purchasing 2SD555's. There a lot of fakes out there. I know, I have purchased fakes and they will blow. I think they were just something like a generic 2N3055 that they grit blasted the original markings off, then re-labeled as a 2SD555. I doubt you can still get the real NEC version any longer, and if you want beta matched devices you best buy plenty of extras if you can even find the real thing.
That may be, on paper, but the NEC replacements used are true to the design. They are the original OEM NEC transistors. Not substituting with transistors that may be counterfeited. No one knows the circumstances under which the channel broke down originally, over the course of a very hard life. Last check the unit is operating fine. Thank you for visiting.
Dude you are the greatest ! I would have been scared to death damn near to go anywhere near that amplifier with a pointed probe like that ! You got the job done !
I had my HR-752 and TFM-35 rebuilt by a fella in Oregon. I'm so glad I did. Added a decent set of speakers, and it sounds as good or better than most receivers you can easily dump $1,000+.
Ahhhhh the joys of Bob Carver! Serviced many a Carver power amp back in the 90's. I loved em. Quirky indeed but they do pack a punch. :o)
very good, bat not subtitles for traslate? ?????
I have had Bob Carver amps, speakers, subs, tube cd players and so on for 35 years. NO ONE would EVER fix the very few things that went wrong, I shorted a channel on an amp by drilling through speaker cable. Everyone said that Carver amps are CRAZY and they will not touch them. Well I have 40 year old amps still going strong, I'll take crazy any day, Thanks for the video, it shows how tough they are to work on, Bob Carver, Mad Scientist
Follow the service manual, it´s very easy to fry the transformer as the power lines will switch rapidly when poking in the signal level like that, if the triac blows or is short. Lock the supply line level when working like that. You do not need full line voltage untill everything is in order for load test.
Nice work! Those Carver amps really pack a punch. The peak ESR meters arent supposed to be fussy about correct polarity, so those readings were probably correct
VERY good job, congratulations! A cheap infrared thermometer would be useful to check the temp. in the output transistors.
A friend give to me a Carver PM-1200. It's a creepy beast, can blow any "home" speaker in a blink of an eye. It was given away because it is on 110V, i have to convert it to 220 (Local mains here). There is a service note to do that, but it is VERY risky business with all those high DC voltages.
Very nice work, congrats , i like to fix and rescue amplifiers too, but y do as a hobby.
15:49 check bias adjustments and voltage lines...
THat MPSU T0-202 ...was it mounted to the bottom plate?
I believe so. Thank you for watching!
One thing to be careful of is those D555 transistors that looked like the label was scraped off and reprinted have a high probability of being counterfeit transistors. I have seen them and they do not tend to last. Any transistor that has the mark altered or indication of sanding throws up red flags.
That is true. Did investigate that silkscreen, & seems these are NEC.
Yeah they maybe a pain to work on but IMO those are cool designs. If you look at how the air system works on those amps its one of the most cleaver designs for cooling on a rack mount type amp ive seen. I actually like its design.
nice work! i've got a pm 1.5 that works great but it sounds like the fan is going out. any recommendations on where to get a fan motor?
It's a domestic product, shouldn't be too hard. It may be thermostatically controlled & not run at all times.
@@Farmradio , it has a "silent" switch which slows the fan down, but when the switch is off, fan runs normal speed, when power to unit is switched on with no load.
i wonder how long that worked...
Love the Music
450 watts per channel and 1100 in mono.
I have one of these that still works. Be careful about purchasing 2SD555's. There a lot of fakes out there. I know, I have purchased fakes and they will blow. I think they were just something like a generic 2N3055 that they grit blasted the original markings off, then re-labeled as a 2SD555. I doubt you can still get the real NEC version any longer, and if you want beta matched devices you best buy plenty of extras if you can even find the real thing.
2sd555 are peak 160volt , those 555 are not good the have only 120volt peak
That may be, on paper, but the NEC replacements used are true to the design. They are the original OEM NEC transistors. Not substituting with transistors that may be counterfeited. No one knows the circumstances under which the channel broke down originally, over the course of a very hard life. Last check the unit is operating fine. Thank you for visiting.