ram@tellabs.com (Bob Martin) (11/15/90)
About 8 or 9 days ago, someone posted a question about other sources of memory cards (in this case, a Korg keyboard). No one has replied to his question, and I was wondering why. I told a friend of mine about this article, and he said the net had already been through this subject last spring, so I'm curious why nobody has posted a synopsis of what was determined back then. Below are some details of what my friend can remember. The memory cards in the HP (ROM, RAM, etc.) are a standard format found in many products, specifically laptop/handheld gadgets and music keyboards/synths. Most of them are made by Epson, and are pretty much interchangeable. Epson makes the RAM unit for HP, but HP spec'ed some special parts, so the HP model is more expensive. From what I can gather, the voltage regulator in the normal part is too sensitive when used in a 48, since the 48 runs at less than 5VDC. HPs part has a different regulator. I think the other cards will work in a 48, but when battery power gets low, you could lose what's in the RAM card. If this is correct, then if you make sure to always change batteries before they get low, you should be able to use these cards (this is an assumption on my part). If anybody has any reliable information, please post. The reason I care is that I (anybody, actually) can get these standard RAM cards (128KB) for $60 apiece mail order. BEGGING mode on: Would the guys who have machine language TETRAS please pretty please post it! I'm going nuts waiting for it! Thanks! -- =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=--=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Bob Martin | ram@tellabs.com ...!uunet!tellab5!ram Tellabs, Inc. |"Listen to me now, and believe me later" - Hans & Franz Lisle, IL. 60532 |"Flibble-dee Floo" - Grumpy Old Man
steveh@hpcvra.cv.hp.com.CV.HP.COM (Steve Harper) (11/17/90)
The voltage which the 48 supplies to power the RAM cards is generated by a power supply in the 48, so it does not depend directly on the battery voltage level. Putting fresh batteries in your 48 will not make the so-called "standard" RAM cards work any better when used in the 48. If your 48 IC's happen to have been manufactured such that the output Vdd is on the high side of the spec AND the "standard" card you use happens to have a cut-out voltage on the low side of its spec, then it will work OK... Otherwise, using these cards rather than the HP cards is a rather risky and unreliable choice. There is not a simple way to measure these values, nor is a dealer likely to let you rummage through his stock to find one you like... With mail order there's no choice at all. In all probability the worst that will happen is calculator lock up and memory loss, but in theory at least it is actually possible to damage your calculator if left in the locked up state for a period of time. Steve Harper