Entropy

[JR.]

Received my replacement control board for the coffee roaster, so replaced it and just did a new roast. The hardest thing about this repair was paying for the new control board ($200+) but a new roaster is $1600, and I roast a batch every 5 days.. I did one roast blind, but seeing what is going on is better.

I didn't look into replacing the cooling tray fan yet... that requires a complete tear down and doesn't really affect the roast quality (something else for my to-do later list).

JR

[emrr]

Must be the season. Had the highs diminish in a JBL powered monitor over a couple hours the other day, switched to secondary speakers to get through the session, not my usual constant listening experience. Thought it was probably a tweeter, spent the time to pull and swap tweeters between boxes, and it's something in the amp. Which appears to require total disassembly, and removal of all drivers to get out of the box. And I've got no free time......

Stuff happens... did you try feeding a low level sine wave into the box? This may give some insight about what to look for.

Good luck

JR

That's next, when I can find a moment to take it all apart. The danger for me this time of year is taking it apart, testing, then being unable to get back to it for a month or more, while it's disassembled and strewn all over the place, in the way of other things. Temporary boat anchor.

[JR.]

Sounds like you need some system redundancy... I have two pair of hifi speakers in my living room TV system (one pair actual Peavey/AMR studio monitors) that could be repurposed in a crunch.

You can never have too much gear.

JR

[emrr]

Oh, I'm using the secondary studio speakers, I just don't like relying on them alone. Thee are also two Wohler broadcast monitors of different sizes, useful, but not for client listening. I don't find any of my 'fun' listening home speakers useful for mixing at all, they lead to constant second guessing. There are 3 sets of those at the house.

[mediatechnology]

I expect the stainless steel screw clamp to be adequate for my flag.

Speaking from experience that should last awhile.
Until the stainless steel cuts through flag pole. (If its the crappy thin-wall aluminum ones.)

Speaking of tape recorders...

I made a living out of repairing 1/4" to 2" machines.

I used to also do cassettes but you could never win the "argument" over correct tape speeds.
It didn't matter if the machine measured correctly with a speed tape if it was a fraction of a semi-tone off-pitch to the client it was wrong.
After several years of this I refused to service cassette machines.

By the time DATs rolled around I was smart enough to not go near one for service.
I hope a lot of equipment rests in peace.
DAT machines belong in hell.

[JR.]

I expect the stainless steel screw clamp to be adequate for my flag.

Speaking from experience that should last awhile.
Until the stainless steel cuts through flag pole. (If its the crappy thin-wall aluminum ones.)

Speaking of tape recorders...

I made a living out of repairing 1/4" to 2" machines.

I used to also do cassettes but you could never win the "argument" over correct tape speeds.
It didn't matter if the machine measured correctly with a speed tape if it was a fraction of a semi-tone off-pitch to the client it was wrong.
After several years of this I refused to service cassette machines.

I tried to refuse to design that Karaoke unit with cassette playback but my boss advised me it could be my last argument there.

A surprising number of them use simple DC drive motors with negative impedance speed regulation. Back in the 70's when I was working at the pitch shifting company that made faster playback of talking book cassettes with corrected pitch, we modified cassette decks to vary from 0.6x to 2.5x speed... We added an optical tachometer to the motor for actual speed control.

Yes, I hate cassette decks too, but they were good for what they were... The Peavey/AMR 4T had punch-in capability for all four tracks so besides the already narrow tracks on narrow tape, there were guard bands and head shielding between all 4 tracks. Remarkable they worked as well as they did with that little tape area, and modest speed..

JR

By the time DATs rolled around I was smart enough to not go near one for service.
I hope a lot of equipment rests in peace.
DAT machines belong in hell.

[Gold]

By the time DATs rolled around I was smart enough to not go near one for service.
I hope a lot of equipment rests in peace.
DAT machines belong in hell.

Yeah, they suck. They are really video decks though. I consider helical scan a totally different animal than fixed head. I don't suppose you've ever adjusted pinch roller pressure on a Telefunken M15

[mediatechnology]

By the time DATs rolled around I was smart enough to not go near one for service.
I hope a lot of equipment rests in peace.
DAT machines belong in hell.

Yeah, they suck. They are really video decks though. I consider helical scan a totally different animal than fixed head. I don't suppose you've ever adjusted pinch roller pressure on a Telefunken M15

Never done a Telefunken but I have "re-adjusted" more than my fair share of MCI pinch roller pressure.
Generally the MCIs only needed adjustment if someone had messed with them thinking roller pressure was the problem.
Once the underlying problem was fixed setting the roller pressure was relatively easy.
I stopped using a spring scale for that once i learned how it "felt."
A spring scale is a good reality check.
I still have the "de-Liar" fish scale I originally bought as well as a really nice brass one that's probably collectable by now.
Otari sold some awesome ones.

I spent another full day screwing around with it. No love. Unfortunately I don't have a spring scale so I can't see whether it meets spec. I guess that would indicate it's the pinch roller its self. But the pinch roller looks the same as it did when it worked at 15 ips and feels like it always has.

So its OK at 15 and not at 7.5?
Is the takeup tension supposed to change in that machine when the speed changes?
I'm pretty sure that machine is constant torque and not constant tension.
If its constant torque there may be a resistor or capacitor switched in to alter TU tension with speed.
I don't know jack about a TF though.
Not sure I've even ever seen one.
This was MCI, Otari and Studer country.

[Gold]

Never done a Telefunken but I have "re-adjusted" more than my fair share of MCI pinch roller pressure.
Generally the MCIs only needed adjustment if someone had messed with them thinking roller pressure was the problem.
Once the underlying problem was fixed setting the roller pressure was relatively easy.

I guess it could be the pinch roller its self. The capstan on the M15 is chrome plated and smooth unlike a Studer. The pinch roller has a shiny part where the tape path is. Like you say below t I want the fish scale for a reality check. When I add pressure to the pinch roller with my thumb the tape becomes better centered on the heads and follows the wear pattern on the pinch roller more. So I think something slipped.

So its OK at 15 and not at 7.5?

It was okay playing back coated tapes at 7.5 ips but this whole thing started with a non back coated tape. I've managed to screw things up enough so nothing works now. Yay.

Is the takeup tension supposed to change in that machine when the speed changes?

No but there is a high torque setting with a picture of a DIN reel and a low torque setting with a picture of a cine reel. You can set the fast wind takeup reel tension separately for each position. Rewind is set with a thumbwheel under the takeup reel for both tension positions. The replay tension has only one setting on a thumb wheel for both speeds.

I'm pretty sure that machine is constant torque and not constant tension.

I think it's constant tension. In other words the speed doesn't change over the course of a reel unlike an Ampex 440 or the like.

[Gold]

Never done a Telefunken but I have "re-adjusted" more than my fair share of MCI pinch roller pressure.
Generally the MCIs only needed adjustment if someone had messed with them thinking roller pressure was the problem.
Once the underlying problem was fixed setting the roller pressure was relatively easy.

I guess it could be the pinch roller its self. The capstan on the M15 is chrome plated and smooth unlike a Studer. The pinch roller has a shiny part where the tape path is. It is unlike the Studer where the capstan and the pinch roller aren't supposed to look smooth. Like you say below t I want the fish scale for a reality check. When I add pressure to the pinch roller with my thumb the tape becomes better centered on the heads and follows the wear pattern on the pinch roller more. So I think something slipped.

So its OK at 15 and not at 7.5?

It was okay playing back coated tapes at 7.5 ips but this whole thing started with a non back coated tape. I've managed to screw things up enough so nothing works now. Yay.

Is the takeup tension supposed to change in that machine when the speed changes?

No but there is a high torque setting with a picture of a DIN reel and a low torque setting with a picture of a cine reel. You can set the fast wind takeup reel tension separately for each position. Rewind is set with a thumbwheel under the takeup reel for both tension positions. The replay tension has only one setting on a thumb wheel for both speeds.

I'm pretty sure that machine is constant torque and not constant tension.

I think it's constant tension. In other words the speed doesn't change over the course of a reel unlike an Ampex 440 or the like.