Mark VIe is the generation that follows Mark VI, and Mark VIeS is its safety-rated sibling. Boards carry the IS400 and IS420 prefixes — distinct from the IS200 / IS210 / IS215 numbers of the Mark VI, and not interchangeable with them.
The safety distinction matters more here than anywhere else
Mark VIeS is a safety system. Boards such as the UCSB safety processing module exist to perform a protective function to a defined integrity level. That has a hard consequence for procurement:
Do not substitute across the safety boundary. A board that is functionally similar but is not the safety-rated part is not a replacement, regardless of what it appears to do on a bench. If the board you are replacing sits in a Mark VIeS safety path, say so in your quote request and we will not offer you anything else.
What you will find in this family
- UCSB — safety processing board, Mark VIe and Mark VIeS.
- YVIB — vibration input and output module.
- CCGA — control communication gateway.
- AEBM — AE bridge module.
- TDBT and the terminal board families — the field-wiring landing points. As on every Speedtronic generation, a failed terminal board looks identical to a failed processing module from the HMI. Ring them out before condemning an expensive card.
Condition codes you will see on these listings
Mark VIe parts are recent enough that new surplus genuinely exists, which is not true of the older generations. Two abbreviations recur:
- NSFP — new surplus, factory packaged. Never installed, still in GE packaging.
- NSNB — new surplus, no box. Never installed, packaging gone.
For a safety-path board, NSFP is worth paying for. It has never been through a thermal cycle in a turbine cabinet, and its provenance is unambiguous.
Reading the number
IS420UCSBS1A splits into the family prefix (IS420, Mark VIe / VIeS), the functional acronym (UCSB), and the trailing revision digits. As with every Speedtronic generation, the same board is listed under a short number and a longer one carrying the revision tail — IS400AEBMH4A and IS400AEBMH4AJD, for instance, are the same board. Search both forms.
Requesting a quote
Send us the full part number with the revision tail, whether the board sits in a safety path (Mark VIeS), the rack and slot, the condition you can accept, and whether this is a breakdown or a shelf spare. We reply within 24 hours, ship worldwide DDP, and accept purchase orders.