These ROMs provided courtesy Luis Cupido, CT1DMK 
(cupido (at) mail.ua.pt):

	Find attached the original roms and a file
	with full addr space form 0h to ffffh
	of the rom contents of the last version of the 492
	I'm aware the v1.6.

	Not knowing what configuration of roms will be used
	on that memory board, from the full addr range you get it all.
	(could either be a 2715 and two mosteks 8keach
	or a 2716 and 4 mosteks(or2732) 4k each
	or a modified board with a single 27c512
	or a modified board with a 27c16 and a 27c256
	you decide ;-)

	Used addrs are:
		1800h 2k
		c000h 8K
		e000h 8k

The TK492ALL.ROM file contains all of the firmware in one ROM 
image, which can be installed according to Luis's notes in 
tek_492rom_mod.jpg.  Luis writes:

	The mostek eproms may lose contents and one may not find
	a suitable programmer or they may not erase or not accept
	new programming, that is they are lost.
	It may not be easy to find replacements and we may not find
	also a suitable programmer.

	Solution is to put all code on a single 27C256 replacing
	the address space of the four mostek proms (8000-FFFF).

	For that a modification is required that we apply a 28pin socket
	to the first empty socket position (the 49x analyzers only
	use the last two sockets) not connecting pin 24 (now pin 26) and
	wiring it according to the diagram.
	The capacitor below U2012 must be removed.

	the U1012 is a 2716 and there is no need to
	replace this one as 2716 eproms can be found
	and programmers for those are easily available.

John Miles, KE5FX (jmiles@pop.net)
September 29, 2009