Fostex XR-7 Multitracker | Review & Tear Down

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Here's a brief review and complete tear down of the fostex XR-7 which I recently refurbished for its owner. Its a nice cassette 4 track which suffers little ffrom Fostex's propensity for weird layouts and misbalance of features, and arguably the dolby NR sounds better than the DBX common to yamaha and Tascam contemporaries. I suppose there are things about it where i'd prefer a tascam 464 or 424 MK III, but those units porbably cost more at the time and still in the secodn hand unit. Nice unit overall.
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CHAPTERS
0:00 Introduction
0:24 Size and weight
0:47 Tape speed
1:28 Dolby Noise reduction
1:34 Record modes & ping-pong recording
02:22 Send effects via the auxillary buss
02:55 Equalization
03:32 Output sockets and monitoring options
04:15 Digital tape controls
04:41 My thoughts on the XR-7
05:29 TEAR DOWN BEGINS - remove plastic knobs
06:26 A caveat regarding screw lengths
07:24 Opening the case
08:53 Acessing the cassette player
10:04 Use sharpies to make reassembly less confusing
11:28 A layman's guide to circuit ground
13:59 An overview of how the cassette player works
15:07 Motor model, operation and substitutes
16:01 Changing the belts & cleaning the pinch roller
18:22 Detaching the printed circuit boards from the plastic case
18:34 Power switch and input socket
19:59 Shuttle controls
21:34 Door mechanism
22:13 Output sockets & mixer
25:57 Trimpots for calibration

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Опубликовано:

12 июл 2024

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Комментарии : 18

@neilpatterson5705 3 месяца назад

Hi Calum, I've now had chance to watch the full video. It's fascinating to see you confidentally strip the X7 down to its component level. As your client in this particular instance, its really reassuring to actually see how thoroughly you go about the business of servicing the unit. It looks & feels like new now that its back home. Once I've got some free time I'll give it a decent workout and will share the results with you. Thanks again, Neil.

@Tetrakan 3 месяца назад

Thanks Neil. Honestly, I received this unit in a good condition and I didn’t have to do that much to it other than clean it properly and give the trimpots a bit of a tune up. I hope I postponed or prevented issues in the future, but really, it was in a good place to begin with! I hope you get a lot of pleasure from working with it.

@xisotopex 16 дней назад

hopefully this video can help me put my x77 back together.... I took it apart on a whim to try to see if I coudl fix it, which I could not, but I waited too long to try to reassemble it.... and its is a complicated sandwich to get back together....

@PORTA777 3 месяца назад

Thanks to your post, I have been able to repair several cars so far. Although it is a portaone, I can hear the input sound and can record to tape, and the tape works when playing back, but the VU meter does not move and there is no sound. Can I get some advice?

@mysterexmarsta3004 Месяц назад

Hi there do you re condition 4 tack recorders as a business? i have a Yamahah mt and forst xr7 that could do with a service

@quikstiks4781 3 месяца назад

I picked up one of these a while back, but it seems that most units on the market are missing the plastic printed level cover. Any ideas where I could pick one up?

@Tetrakan 3 месяца назад

You really need spares donors for those sorts of things unfortunately.

@DiegoCarvacho 3 месяца назад

hi, first of all thanks for sharing your knowledge!! more people should me as generous as you... I have a question regarding a tascam 424 mk1 that I have and been trying to get to work properly for long while now... The problem that I have is that after recording the same test tone signal on all 4 tracks simultaneously, when I reproduce the recording Track 1-3 are OK with levels but track 4 starts very low and increases level with time.. it takes about a minute or so for the signal to get close the the other 3 tracks. Since this issue has to do with time, do you think track 4 needs new capacitors? if not, do you have any idea of what might be the cause of this issue? Thanks a lot! Diego.

@DiegoCarvacho 3 месяца назад

by the way, if I reproduce a test cassette (full track) the levels are equal on all four tracks at all times. I'm lost here.

@Tetrakan 3 месяца назад

Honestly I’ve never had a problem like that….yes I think something is taking time to heat or charge, and if it’s not a capacitor then I guess it’d be a semiconductor, but at the end of the day my process is always the same; isolate where the problem is occurring, get as many clues as I can using probing with an audio probe, scope or meter, do a check for physical issues like loose cables, cracked boards, loose or missing inductor cores, heat damage or dry joints, then if I haven’t already figured out exactly what has gone wrong, start replacing components near the fault working from the most obvious culprits to the least. Electrolytic capacitors separating gain stages and smoothing the power to opamps are among the most common things I have to do to get a portastudio working, especially where there is low signal in an amplifier stage, so failing anything obviously broken or disconnected in that area of the bottom board, start with electrolytic caps in the track 4 record amplifier. Failing that, semiconductors such as the opamp chips themselves tend to fail less often than electrolytic caps, but more often than other types of caps. Resistors tend to fail least often and obviously look bad when they are damaged but you never know. Good luck!

@xisotopex 16 дней назад

how do you compare this to the tascam 246? thinking of replacing this with a 246

@Tetrakan 14 дней назад

I think most people would agree the 2346 is better overall - more richly featured, more stable cassette player.BUT Its also a lot buigger and heavier and you might miss haveing high and low shelf EQ. And a lot of folks including me prefer dolby NR to DBX, so theres that. Could be worth having both for reduction mixes, backwads compatibility with dolby encoded recordings.

@neilpatterson5705 3 месяца назад

Looks familiar 😉

@valleywoodstudio7345 3 месяца назад

Seems a nice design for servicing and especially calibrating with the ability to hinge across to one side - mind you, I wonder how many actually ever got to a service department over their lifetime? Re the ribbons - it is the same on the 380s I just got up and running. For me they were a little better and easier to reconnect than they initially appeared - ymmv!

@michaelboutwell6389 3 месяца назад

I hope some one can help: On my Yamaha MT8X there are two switches to the side of the center motor soldered with four prongs each into a small board that tell the machine it has a cassette plugged in. I have researched even the service manual but I still can't figure out what they are called so I can replace them. Can anyone help?

@Tetrakan 3 месяца назад

The generic name is leaf switches. If you can’t find a suitable size of replacement, it’s easy to just bridge the two halves of where the old switch joins the circuit board, the unit will then just think a cassette is always present. It’d mean the capstan motor turned whenever the unit was powered on, but most tascam work that way anyway.

@xisotopex 16 дней назад

are you wearing an Entombed t shirt?? RIP Lars Petrov

@Tetrakan 14 дней назад

It isn't, but I like the band. Might be a Conan shirt? The logos are kind of similar