There is much more on resonating the head, eq curves, over bias level, bias traps on and on. Bias oscillator distortion and frequency (+level).
Check 3M (Quantagy I think now) and Ampex for more technical information. TDK in Japan may be interesting if they are still with us.
I have no idea what make and model of recording machines there are for test tapes. Studer, MCI / Sony, Ampex - who knows.
There is no way I can remember everything I learned over 25 + years. My memory is a little hazy as it is on these things. My referance material when with my business when I sold it. Just be glad you aren't trying to fix an 8 track!
-Chris
Check 3M (Quantagy I think now) and Ampex for more technical information. TDK in Japan may be interesting if they are still with us.
I have no idea what make and model of recording machines there are for test tapes. Studer, MCI / Sony, Ampex - who knows.
There is no way I can remember everything I learned over 25 + years. My memory is a little hazy as it is on these things. My referance material when with my business when I sold it. Just be glad you aren't trying to fix an 8 track!
-Chris
Oh I love this thread ... 
I`m in the IT business now gor more than 10 years ... Back then I started as service technician. I remember telling my boss I can fix anything. Well he sent me once to a customer where a server had problems. I didn't knew that already 5 technicians have tried to solve the problem and didn't cope with it. This was meant as a joke because my boss wanted to give me some sort of a lesson. Amazingly I solved the problem. So, everybody wanted to know how I did it. Well the problem was that I was not afraid to make changes and I changed everything wich come strange to me and the server worked again ... But i didn`t knew what I`ve done ...
Since then this happened to me a couple of times and I never broke something. I don't know what an 8 track for a challange is but recently I`ve aquired a Tektronix scope. I've dismantled it completely, cleaned it, changed some bad parts and I've put it together, tuned it - it works. I must say I don't understand much of electronics, ok I have a sevice manual ... But using your brain, having a shematic and just a little analytical thinking can do wonders. The scope is a 475 Tektronix. It was a pain because it is really jammed with parts, but that was also a nice challenge. So, is an 8 track more complicated than a 475 Tektronix scope ?) Thank you again for the information.
Best regards,
Plamen
I`m in the IT business now gor more than 10 years ... Back then I started as service technician. I remember telling my boss I can fix anything. Well he sent me once to a customer where a server had problems. I didn't knew that already 5 technicians have tried to solve the problem and didn't cope with it. This was meant as a joke because my boss wanted to give me some sort of a lesson. Amazingly I solved the problem. So, everybody wanted to know how I did it. Well the problem was that I was not afraid to make changes and I changed everything wich come strange to me and the server worked again ... But i didn`t knew what I`ve done ...
Since then this happened to me a couple of times and I never broke something. I don't know what an 8 track for a challange is but recently I`ve aquired a Tektronix scope. I've dismantled it completely, cleaned it, changed some bad parts and I've put it together, tuned it - it works. I must say I don't understand much of electronics, ok I have a sevice manual ... But using your brain, having a shematic and just a little analytical thinking can do wonders. The scope is a 475 Tektronix. It was a pain because it is really jammed with parts, but that was also a nice challenge. So, is an 8 track more complicated than a 475 Tektronix scope ?
) Thank you again for the information.Best regards,
Plamen
Hi Plamen,
An 8 track is different. The tape rubs on itself and wears as a result. That and it is a very old format. Just a bad situation and a bit of a joke.
Unlike a server (and like in some ways), you can get a product running, but not to factory spec in electronics. Or the product will fail later due to some related issue. So I don't classify a unit repaired until it does in fact run properly and to factory spec. That and with a resonable expectation that it will run for 5 ~ 10 years.
You have a good 'scope. The very fact that some things were physically moved may throw it out of calibration. This would be more so at high frequencies. You are right that given a schematic and some clear thought, you can get most things working. It's the little things that will get you (same as networking). The details are the killer and this is where a good tech makes all the difference.
-Chris
An 8 track is different. The tape rubs on itself and wears as a result. That and it is a very old format. Just a bad situation and a bit of a joke.
Unlike a server (and like in some ways), you can get a product running, but not to factory spec in electronics. Or the product will fail later due to some related issue. So I don't classify a unit repaired until it does in fact run properly and to factory spec. That and with a resonable expectation that it will run for 5 ~ 10 years.
You have a good 'scope. The very fact that some things were physically moved may throw it out of calibration. This would be more so at high frequencies. You are right that given a schematic and some clear thought, you can get most things working. It's the little things that will get you (same as networking). The details are the killer and this is where a good tech makes all the difference.
-Chris
Hmm ... The 8 track decks are not very popular here in europe. So, I`ve never seen one. I`don`t even know which model is the best at all. Bit indeed, this is a very old technology and I don`t know if there are really good quality recordings left. The only reason to get such a deck is in order to hear quadro recordings. But I would prefer vinyl for that. Speaking about quadro, another thing is that it is impossible to find a Fosgate tete decoder, or at least not here in europe. I`ve read many good things about it and I would want to have one but ... No way here in germany. Perhaps I`ll look for one when I come to the states. )
Best regards,
Plamen
)Best regards,
Plamen
By the way calibration of decks. I have now a dragon on my bench. It is a good unit. The azimuth adjustment didn`t work and i replaced a bad transistor, one of the two wich drive the motor. Well everything is ok and I`m using new TDK MA-XG cassettes to make tests and recording. So i recorded a full cassette with music. Everything as expected. But I noticed a very weard behaviour. When I play forward, everything ok. But on reverse playback the azimuth motor goes left-right during the first piece of music. Only in reverse playback, only at the beginning, not in the middle of the cassette. And only with MA-XG recorded with this deck. So, I think I did`t adjust the phase in reverse playback mode properly, or there is something with the transport. i dismantled everything, cleaned, relubed, adjusted with the proper tools. Perhaps I`ve done an error with the reverse playback guide, this on the right side. I`ve checked with a mirror cassette ... The tape is not idling back and forth. I`m just wandering what is the cause of this behaviour. What do you think ?
As of the scope, indeed a good one, I`l send it soon to calibration, but as of now it works fine.
Best regards,
Plamen
As of the scope, indeed a good one, I`l send it soon to calibration, but as of now it works fine.
Best regards,
Plamen
Hi Plamen,
Well, metal tape is one way of destroying a Nak head. I would use a TDK SA or SAX. That's the base for Nakamichi reference tape (SA).
The hunting could be caused by tape tension in the reverse direction. You may also have worn capstan bearings (part of the motor assy.). I used to buy just the front half of the motor. Iffy pinch rollers may also be at fault.
-Chris
Well, metal tape is one way of destroying a Nak head. I would use a TDK SA or SAX. That's the base for Nakamichi reference tape (SA).
The hunting could be caused by tape tension in the reverse direction. You may also have worn capstan bearings (part of the motor assy.). I used to buy just the front half of the motor. Iffy pinch rollers may also be at fault.
-Chris
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