A-4010SL service manual

[David57]

A place I found to purchase a service manual from has the A-4010S and the A-4010GSL, of course I need the SL version.

If my understanding is correct the S version of the manual will do me little good because for one reason the SL added front panel bias controls, so even if the mechanical adjustments are the same the circuitry is bound to be different.

But what about the GSL? Will a GSL service manual do me any good with my SL? My understanding is that the GSL has different heads, but is the circuitry and mechanics the same?

[Jonny Ramone]

I have one of these decks. I have a PDF manual I can Email you, but it's not real legible. My GSL pdf says"damaged". I'll send what I have. What is the problem you're having?

[David57]

Jonny,
This Reel to Reel is new to me and I want to go over it completely to be sure it is as close to spec as I can get it and perhaps do the mods suggested by the pro's here at tapeheads for proper modern tape bias.
I will PM you my email.
Thanks,
David

[Jonny Ramone]

Make sure your heads aren't worn out before a substantial investment. Mine are worn, but not worn out. I plan on re-capping in the future, but I have about 100 reels of brown oxide tapes to use, so I'm not adjusting for modern tape. You may want to try it with period tape first. I've been pleasantly surprised at the performance.

[Skywavebe]

Hi David57,
The difference might be a lot if you find out the audio section has an crazy staggered op amp in it instead of discrete transistors. I have a A7010SL in the shop now with a series of problems. All of them have been resolved except for the missing left channel of record. This unit has brand new head stack on it that was found on E bay. These are all Ferrite heads. The only way this unit will be fixed at this point is for me to design a new modern day op amp circuit to retrofit the electronics in this customers machine. It is just a matter of a proto board and socketed op amp and some other resistors and wire of course.
The Record EQ caps are made large in these older units because no one made great tape in those days- Scotch 203 was probably tops. This was not by today's standard a very good tape. I calibrate my older machines to RMGI LPR35 which is very close to Maxell XL I formula. With the right component replacements and adjustments I am sure this tape will make the specs of the deck better than original. The person adjusting has to have a complete understanding of the recording process to get things right starting with heads that are in specs and not with open gaps.
See what is in your unit and match to what documentation you have and if they match then you are in good shape. Record EQ wise, I start by cutting the boost in half or so. The 7.5 KHz boost is not needed with the new tape and if not lessened then it makes you increase the bias until the bandwidth is severely limited. A deck with good heads and good tape should be able to record at 0 VU reference to 200 nWb/M flux density from 40Hz to 21KHz at 7.5 IPS. With worn heads of 50 to 60% then maybe a little lower than that. Low speed (3.75 IPS0 is usually limited to under 13KHz due to the speed. At -20 dB from 0 VU it looks a lot better but no one I know records like that. It is a misleading spec.

[David57]

Jonny, I will check the heads. If I can get a good macro shot of one of them I will post it, maybe best in a new thread. I don’t have any prerecorded tape, but I do have some new Quantegy 456 to make some mixes on. The manual you sent is legible enough to get me started on the transport, thanks.

Skywavebe, thanks for checking in and for being such a great resource here at Tapeheads. Sounds like the 7010 is a good bit of work. I don’t know how far I will be able to go with Reel to Reel machines as I do not have a calibrated tape. I do have a good scope and a sig gen though. I recently got a 6010 working for a friend . That service manual said you could remove the heads and inject a signal at the head stack socket for playback amp check. So that’s the limit of my restoration at this point. Thanks for the info.

For anyone else stumbling on this thread curious about manuals it appears most of the transports and transport circuitry are very similar in this 4010 series, but if you need to work on the amp section you need to be very specific. It’s not very likely that a GSL manual will help you with the SL play/record amp circuitry like I have seen some sellers suggest.

*reelspin**reelspin*