The RCA 6499 Radechon is barrier-grid charge storage tube, first produced by RCA in 1956, and used in such systems as the SAGE defence computer. The 6499 uses an electron beam to store data on a charged target. Much like modern DRAM, the contents of memory must be continually refreshed in order to be maintained. The 6499 has a maximum storage capacity of 16,000 random-access bits, though its practical capacity is somewhat less, due to splatter on adjacent bits from the electron beam.![](../pics/aaj0301e.jpg)
Simplified diagram.![](../pics/aaj0301a.jpg)
The gun assembly within the clear tube. Under the colloidal graphite coating are the two sets of deflecting plates.![](../pics/aaj0301b.jpg)
The circular barrier grid.![](../pics/aaj0301c.jpg)
The face-plate with additional connections to backing plate and grid 5.![](../pics/aaj0301d.jpg)
Another view.![](../pics/aaj0301f.jpg)
The woven mesh barrier grid g5 showing the holes.![](../pics/aaj0301g.jpg)
Imaging the wires through the glass was not 100% successful.The end window envelope is 50 mm in diameter and, excluding the B14A base pins, is 278 mm tall. |
Pin Connections
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | ![](../static/key.gif) h | k | g1 | ic | g3 | nc | J4 | J3 | g2,g4 | J2 | J1 | nc | ic | h |
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Absolute Maximum Operating Conditions¶
CRT | Vh | Ah | ![](../static/pdflogo.gif)
| 6.3 | 0.6 |
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Updated January 06, 2022.
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