Tape Topics

Ten Ten - A look inside the new recorder

 I have just finished analyzing the new Atari 1010 cassette recorder. The new recorder turned out to be better than I expected, but not as good as I hoped.

 The new package design was done by someone who really knows their business. The design is neat, with very little wasted space. The internal connections to the circuit board are made with detachable connectors to make the recorder more serviceable. External connections were also changed to removable connectors, as was done with the 810 disk drives. These are welcome design improvements. The new package is designed to match the look of the disk drives, so the recorder looks more like a proper part of your computer system. The old 410 looked like a stray.

 The most important improvement in the new design is the addition of two I / O connector ports on the back of the recorder. These connectors allow you to put the recorder anywhere in the peripheral chain. The recorder no longer has to be the last item in the daisy-chain. This simple change in the design will improve the performance of cassette loads for those people who also have disk drives. Why? Because every connector in the daisy-chain introduces a little more noise into the system; and a bad connection will introduce a LOT of noise into the system. This design change was a good engineering move.

 Another new aspect of the 1010 is that is has its own itty-bitty power pack similar to the ones used by the disk drives, but much smaller. This power pack plugs into the back end of the 1010 with the same kind of connector everything else in the system uses. This was another good move. The power transformer in the 410 recorder is permanently mounted inside the main recorder housing. The new detachable design makes maintenance easier. Although I don't believe that magnetic interference from the transformer was large enough to be any problem in the 410, you eliminate the possibility altogether by removing the transformer from the main housing.

 I do have a few complaints about the new design. The access hole for doing head alignment, like that in the 410, is hidden under the label plate just above the buttons. This was a mere annoyance with the 410, but Atari decided to use a much stronger glue this time, so you almost need a crow bar to remove the plate. I couldn't remove it without damaging it. I guess this was done to convince you to get your heads aligned at a service center.

 Next month's column describes how to do your own alignment at home. If anyone figures out how to remove the plate without damaging it, please let me know. Also, I can't figure out why Atari put three access holes under the label plate. The one for head alignment I understand, but the other two are a mystery to me.

 The circuit design of the digital play-back circuit is basically the same as that in the 410 recorder. This is a shame. The only real improvement in the circuit is that Atari went to five-percent resistors in the filter amplifiers. The actual performance of the circuit is little better than the 410. I really wish they had gone to phaselocked loops, but maybe they are saving that evolutionary step for a future 2010 recorder. I wonder if Atari would accept a good phase-lock, loop-circuit design if I offered them one?

 One weird thing about the new 1010 is the LED "Power Indicator". I can understand the utility of a light that comes on whenever the cassette is on; but I fail to see the reason for installing a special LED that does nothing more than tell you that the recorder is plugged in. Yes, you heard me right. Atari installed a new "power indicator" that comes on when you plug the recorder in and stays on until you unplug the recorder. As Alice said, "curiouser and curiouser"!

 The first thing I did was rewire the LED. To do this, disconnect the "goldband" end R141 from the circuit board and connect it to the "gold-band" of end of R140 by soldering a small wire (see the board in your 1010 recorder and look right next to the LED connector). Make sure this new connection does not accidentally reconnect to the circuit board. This small modification changes the function of the LED so it will only come on when the PLAY, RECORD, FAST-FORWARD or REWIND buttons are pressed. I would have preferred to change it so the LED would light up only when the cassette motor was on in PLAY or RECORD, but that would have required cutting some traces and installing some additional circuitry. It wasn't worth the effort.

 All in all, I don't think the new 1010 is significantly better than the 410. Over the last four weeks, it has performed about the same as my unmodified 410 recorder. If you have a 410, don't rush out and buy the new 1010. You will be better off installing the hi-rel modification I discussed earlier (April, '83). If you don't have an Atari recorder yet and really need to get a new one, then you might as well get the 1010 recorder. The bottom line is that the new 1010 is a slight improvement over the 410, but Atari still has a long way to go before they will have what I would call a good recorder.

 One final word before I bop off this month. I have received a number of letters from you complaining that your local Radio Shack stores don't carry one percent resistors. You are right. Radio Shack does not carry one percent resistors. The fault is mine.

 First, I should explain what I meant by "one percent" vs. "ten percent" resistors. The answer is not what you might think. The easiest way to explain is by using an example. Let's take the case of a typical 240K -ohm resistor. When these resistors are first tested, the manufacturer sets the measuring equipment at 240K ohms plus or minus one percent. Therefore, any resistors whose resistance is between 237.6K and 242.4K pass this test and are labeled "one percent" resistors. The resistors that flunked this test are then tested with the equipment set at 240K plus or minus two, five, ten and maybe even twenty percent depending upon how many fail at each level. So, a "ten percent" resistor is really a resistor with a resistance somewhere between (for our 240K ohm case) 216K and 264K. Whatever the resistor's exact resistance, it is still called a 240K resistor. Any given resistor may not vary more than a fraction of a percent around its actual value, but it is still rated based upon the screening test relative to the nominal value of 240K!

 Okay, now I can tell you how to get a "one percent" resistor from Radio Shack. All you have to do is buy one of their bulk resistor packs, all of which are supposedly 240K resistors, and use an ohmmeter to find one that really is 240K (plus or minus 2.4K). Cheap resistors like those usually don't go through the extensive screening tests that I just told you about, so the values will vary all over the place. I hope that his helps to clear up some of the confusion.

 The only real difference between what a vendor calls a "one percent" and a "ten percent" resistor is price. If you want to get a real one percent resistor for the hi rel mod, then call up any good electronics supply house and ask for these two part numbers: RN-55-D-2433-F and RN-55-D-3323-F. These are the standard industry part numbers for 1/ 10-watt precision metal film resistors. You will be safe enough with 1/10 watt since the power dissipation in that part of the playback circuit is less than a 1/1000 watt.

 By the way, I was able to find the needed resistors at a local electronics supply store (38 cents each, minimum purchase 25) with two phone calls spaced over about ten minutes. You might not be able to locate them quite as fast as I did, but I trust you won't find your quest as impossible as some of your letters would try to make me believe.