Fostex e16 bargraph meters crazyness

[lovebuzz]

Hello everyone! My first post here...

I am looking for someone with expertise in Fostex e16 calibrating and fault diagnosis.. Well, actually anyone who ever worked with these machines...

See, my e16 was working ok until last week when during routine REP/REC calibration something weird happened to them meters.

Well, the problem is - while in REC mode the input levels bargraphs are 4 db lower than actual signal is... I mean I am feeding my Fostex with 1kHz -10dbv and it was used to show "0" on bargraphs before (just as it should), but now it shows -4 db, even though measuring output by AC voltmeter indicates correct figure (-10dbv, the same as what I feed it with).

Now, if I record this signal and play it back, then bar-graph shows correct value of zero (-10dbv). And also when I play my test-tape (1kHz section) it shows "0" as well, so it's not a problem of meter calibration.. but what it is then?? Maybe you have some ideas?
Anyone? Please?

 

[A Reel Person]

...

On Tascam R/R calibration there is a "meter cal" trim pot that adjusts the accuracy of the meters before anything downstream gets adjusted. Not sure if that's the case with you, as you say it reads accurately on playback. I'll agree that's weird.

 

[miroslav]

Not sure if it's identical on the E as it is on the G.....but my G16 has options to change how the meters read signals...it's used for calibration purposes mostly.

If the E has the same options, maybe you accidentally switched modes....?
Do you have a manual...?....check for anything relating to meter adjustment.

Of course, if you were messing with the trim pot for the meters, then maybe that's the problem.

 

[lovebuzz]

On Tascam R/R calibration there is a "meter cal" trim pot that adjusts the accuracy of the meters before anything downstream gets adjusted. Not sure if that's the case with you, as you say it reads accurately on playback. I'll agree that's weird.

Yes, it's the same with Fostex - there is "meter cal" trim pot, but it's the same one for both reproduction and recording So like I said it shows correct value for test-tape reference section and also for signal recorded by me.. So if I'd adjust "meter cal" in REC mode to indicate 0 db, then my playback would indicates +4db...

 

[lovebuzz]

Not sure if it's identical on the E as it is on the G.....but my G16 has options to change how the meters read signals...it's used for calibration purposes mostly.

If the E has the same options, maybe you accidentally switched modes....?
Do you have a manual...?....check for anything relating to meter adjustment.

Of course, if you were messing with the trim pot for the meters, then maybe that's the problem.

Oh, well, I don't see any option for changing modes of meters... Yes, I have manual, and it only mentions to "Set the NR IN/OUT switch on the recorder rear panel to OUT". It's not the switch you've mentioned though, is it?..

 

[altruistica]

Did you disable NR when you inputted the -10dBv signal?

I setup my MS16 the other day and was scratching my head at one point then realised I'd left the DBX engaged. On my MS-16 ist says the DBX must be dis-engaged when setting up the recorder?
Good luck.
Al

 

[lovebuzz]

Did you disable NR when you inputted the -10dBv signal?

I setup my MS16 the other day and was scratching my head at one point then realised I'd left the DBX engaged. On my MS-16 ist says the DBX must be dis-engaged when setting up the recorder?
Good luck.
Al

Yes, I had it OFF, just as it is mentioned in the manual. Anyways, I was fooling around with Dolby switch the other day and I don't know what exactly I have done, but meters are back to normal now! I tried to recreate the problem, but it is working normally all the time now... well those analog machines are some living beings indeed!

Thanks everyone for the input! Topic's closed I guess

 

[altruistica]

Could it have been oxide build-up in the Dolby switch? Is it one of those sliding switches or a press switch? Repeated switching might have cleared the build-up hence it now working as it should?

Al

 

[lovebuzz]

Could it have been oxide build-up in the Dolby switch? Is it one of those sliding switches or a press switch? Repeated switching might have cleared the build-up hence it now working as it should?

Al

Yes, that's possible... The thing is there are individual Dolby switches on cards for 1st and 16th channels, and one for all channels on the rear panel of E16. Rear panel's one is a sliding one. Ones on channels' repro/rec PCBs are button like.