Teac A-6300 R2R For Repair

There is an original owner A-7300 near me on FB Marketplace. Price dropped from $4K to $2,500. It was a top of the line consumer version similar to the studio version 25-2.

Nice tape pre!

I've been slacking since March. I finally got back on the A-6300. Had some issues calibrating it in March after the recap, just let it sit. Near all the adjusting pots have a plastic shield. Dribbled some DeOxit in them, canned air them out. Much better.



Been watching ebay. Got a nice condition original manual for the A-6300 for $25 shipped.






When taking pics of heads, it helps to have a piece of paper under them to reflect light on them. I tried some thin foam packing material. It's a great diffuser but the heads reflect the irregular surface which hides the true condition of the heads. These have very little wear for the age of deck.

Foam reflector under heads.



Paper reflector under heads.



Hopefully almost done..

Thx Carl! You or Ed need another deck? I have four here, too many. Pioneer RT-71, Teac 4010SU, A-6300 and X-1000r.

When the front edges of the veneered wood sides are beat up worse than the rear, and you don't have Jesse (F1nut) woodworking skills, you repair best you can, drill new dowel holes and flip them 180.

Output and minimum input levels all calibrated well on A-6300 deck two. But, trouble in paradise. Bias trap adjustment, connect scope to test points, press REC and PAUSE, adjust to minimum. I don't expect exact readings between channels, but they should be much closer. Scope channels set to same division.



Even though something isn't quite right, I go to next step, adjust bias. (The bias oscillator spec on this deck is 100kHz +-5%. You need bias to be able to erase/record on the tape).

7kHz signal at -18dB. I can't get the range on the R channel. The SM tells you adjust for peak with trim pots VC401/402, then decrease by 3dB. I can't get much of a peak on R channel. (Teac used the overbias method, but I adjust bias by alternating between 1K and 10k signals but for now something isn't right). OH, I'm really enjoying the two channel dB meter!



One of the trim capacitors doesn't feel right and gives erratic adjustment. I remove VC401/402 trim caps and test. One is 10-76 pf, the other is more fixed, tops out at 46pf (spec is 80pf).



A piece of clear mica falls out of the faulty one. Now I get a better range, but it still tops out at 46pf. I ordered a couple. For now, I reinstall but swap channels.



Now I get this adjusting bias traps. Scope channels set to same division. It's not uncommon for them to be slightly different. Much better! My bias range is much better too but still need to replace the trim pot. Set this on the side until parts get here.



Bias oscillator board VC-401/402 tied into L302/304 bias trap so guessing the broken mica in the trim capacitor was the issue.

On deck pics. First, original side panels repaired, dark Mocha stain to cover the sins and clear satin poly top coat. An untouched OEM side panel at left. My early serial 6300 side panels had a counterbore as they used a shouldered mount washer while the later serial had flat mounting washers.



New Walnut side, Watco Danish oil with satin poly.



The right side Walnut panel.



Left, late side panel mount hardware (17xxx) right, early (11xxx).



I had three Walnut panels to choose from. This one had some dark areas and didn't match first two Walnut side panels, even though you can't see both sides at same time.

The new hardwood sides get a finishing touch. I obtained some aluminum anodized shouldered washers and M4 Phillips head Stainless screws with black finish. (Allen and Torx head are also available). They replace the OEM flat head screws with plastic shouldered washers. Sometimes the OEM screws are in sad shape from poor storage or stripped from using Phillips instead of JIS drivers.

You can get the shouldered aluminum washers in various sizes at ebay or Amazon. They offer different colors too. I went with black on black. I liked the contoured head of these screws better than new flat ones. I guess you could call them a flattened pan head. The seller only had these style M4 screws 60mm long so I cut them down to the 22mm length needed.

I had to use M5 washers as the M4 screw head (8.7mm) is too large for the M4 recess (6.8mm). (They are sized by hole in washer). The recess in the M5 is ~9mm while the head of the M4 screw is ~8.8mm so it's a snug fit. The OD of M5 aluminum washer is the same diameter of the OEM screw head.



I liked the shape and gloss to match washer. One could go with bright stainless screws too.



Other option, flat head with a flatter finish.





A taller Fisheye style washer is available.



Two coats Tung oil.


OEM left.

pitdogg2 wrote: »

By far my favorite wood, for furniture and smoking.

Aaron has me thinking about a Cherry (or ????) cabinet for the X-1000r to replace the OEM fake vinyl wood wrap cabinet. The capability regarding tools is there at his brothers shop for the perfect sized square cabinet. The difficulty is all the thin shim pieces inside. Lots of (cue Hervé, The plane! The plane!) planing work.