US Doubler

by ICD

Chapter 1 -- US DOUBLER OPERATION

After installation, your US Doubler 1050 will be fully compatible with the single and dual density software which you have used before, as well as full double density operation with programs which support that mode.

UltraSpeed Operation
SpartaDOS, also developed by ICD., is the recommended DOS to use with the US Doubler since it opens up the UltraSpeed operation. (Without SpartaDOS, your US Doubler enhanced 1050 will run at normal speed.) This high speed data transfer is accomplished by increasing the SIO baud rate from 19.2K to 54K. The UltraSpeed sector skew then allows 3 times as many sector reads for each revolution of the disk resulting in rapid I/O which sounds like machine gun fire.

Possible Problems with UltrsSpeed and the 130XE
Some 130XE computers have been found which don't like the 54K baud rate and they seem to sputter when reading a sector in UltraSpeed. The solution for this problem is to remove the band width limiting capacitor on the data out line inside your computer. This capacitor (which looks like a diode) will be connected from pin 5 of the 13 pin SIO connector of the 130XE to ground. All you need to do is cut one end of the capacitor and bend it away from the rest. (When facing the back of the computer, pin 5 is in the bottom row, the third pin from the left.) You will notice that each pin on this connector has these capacitors going to ground. The purpose is to filter out a small amount of high frequency noise which may affect television reception. The intention was good but the capacitor on pin 5 also filters out high speed data.

NOTE: the newest 130XEs no longer have these capacitors soldered directly to the connector. Instead, they have them properly laid out on the circuit board to the lower right of the I/O connector. The capacitor you need to cut is C304.

SpartaDOS Availability
SpartaDOS is available on disk as part of the SpartaDOS Construction Set for $39.95 retail or

Your Done!

START-UP AND TESTING

Plug the drive back into your system. If you're going to use UltraSpeed (US), it is usually best to make this drive number one. Put a SpartaDOS Master disk into the drive, close the door, and power up the computer. If you get an error message 'not an XL/XE computer', use the other Master disk. Impressed? The MASTER SpartaDOS diskettes are single density US format. The first few sectors are read at normal speed upon boot; the software determines whether the drive can handle UltraSpeed and then loads the high speed code into your computer. Even though double density sounds slightly slower than single density, the double density US format is even faster since it is working with larger sectors. Refer to the SpartaDOS manual for more information about operation and formats.

If it Doesn't Work
Go over the instructions again and check your work. There is probably something you have overlooked. All of out products are thoroughly tested before shipping to ensure high reliability. If the U8 module is in backwards or not making a good connection, if the jumpers are in the wrong position or if the traces were damaged during de-soldering, the power light will come on but the drive will not spin. If your drive won't boot the master DOS disk then try a standard boot disk of known quality. If you still can't get it to work, send your complete drive to us for repair.

Our service turn around time is generally 48 hours. If there is a problem with our parts, there will be no charges. If there is a problem with your installation, you will be charged a $25.00 flat rate including shipping. If there is a problem with the drive itself, our standard service rate is $40.00 plus parts and shipping. In any case, we will send the repaired drive back to you via UPS COD or prepaid if you include your VISA/MASTERCARD number. For repairs, send the drive and mark the box to:

ICD, Inc.
1220 Rock Street
Rockford, IL 61101-1437

Attn: 1050 Service

Warranty
Be sure to completely fill out and return your warranty card. This is the only way you will be eligible for future updates or enhancements. The warranty is not transferable and is intended for you as the end user only.

Warning! The warranty will be considered null and void if the copyright labels are removed from the ICs or if the hybrid module has been tampered with. We do not support 'pirates' (a nice word for thieves dealing in computer software and hardware; we use other words). We own the copyrights for all our products including SpartaDOS. Any users who are found to be selling or giving away copies of our products forfeit all rights to any support or service. Furthermore, we will take legal action against those users if we feel it necessary or justified.

SPECIAL CONSIDERATIONS

Format
Though the US Doubler is optimized for operation with SpartaDOS, any 'Atari Compatible' DOS should function with it properly. When changing from SpartaDOS to another brand of DOS and using the format command, first turn the drive power off and then back on (cold start) to re-initialize the internal format settings. Failure to do this could create format errors with the other DOS.

•  USD 1050 Board layout. 
  
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•  Request Hex and Bin dump of USD 1050 ROM in ZIP format. 
  
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