Editing BTC 51 series (section)

==Variants==
===5139===
[[Focus layout]].

====5139 E5XKBM111====
<gallery widths="250" heights="187">
File:Packard Bell 5139 -- top.jpg        |
File:Packard Bell 5139 -- branding.jpg   |
File:Packard Bell 5139 -- slider.jpg     |
File:Packard Bell 5139 -- PS-2 plug.jpg  |
File:Packard Bell 5139 -- rear label.jpg | Rear label, with E5XKBM111 FCC ID
</gallery>

====5139 E5XKBM10140====
The model number is not written on this keyboard. The PCB is marked "5139", but then so is the 5149. The layout however is identical the the normal 5139. The similarity in production dates between the PCB and IC suggest high production volume. This keyboard is from 1996.

<gallery widths="250" heights="187">
File:5139 front.jpg       | Front view
File:5139 rear label.jpg  | Rear label
File:5139 controller.jpg  | Intel-based keyboard controller, dated 9614
File:5139 PCB.jpg         | PCB, dated 9613
File:5139 dome sheets.jpg | Dome sheets
File:5139 mount.jpg       | Mount
</gallery>

===5140===
"5140" is the most confusing model number, as it relates to different layouts, eras and connectors. The 5140 number was also used for the Packard Bell 5140M (FCC ID E5XKBM104M10U), a more modern style keyboard of unknown construction but with the same reverse curve shape.<ref>Recycled Goods — [http://www.recycledgoods.com/packard-bell-5140m-keyboard-ps-2-connector-120305-01.html Packard Bell 5140M - Keyboard PS/2 connector (120305-01)]</ref>

====5140 E5XKBM10510====
104-key focus layout, with Windows keys and AT Plug with beige keycaps. PCB marked BTC 5140/7131/7931. The controller is BTC UM6868-03 ( seen on the photos below ), and is dated to the 12th week of 1996.

Possibly there is also ISO-layout version with this FCC ID using controller BTC-marked UM6868A-0021.{{Citation needed}}<gallery widths="250" heights="170">
File:5140 focus front.jpeg|BTC 5140 focus layout front
File:5140 AT Plug.jpg|AT Plug
File:BTC 1540 rear label.jpg|Rear label
File:BTC 1540 PCB.jpg|PCB
File:BTC 5140 ISO Controller.jpg|Controller
</gallery>

====5140 E5XKBM10410====
104-key Focus layout with Windows keys and AT plug. FCC ID is E5XKBM10410; date is not known but it will be 1995 or later.

There's also an ISO-layout version. The sample unit is made in late 1995 according to the date on both the PCB and MCU.

<gallery widths="250" heights="187">
File:BTC 5140 -- top.jpg        | Top
File:BTC 5140 -- AT plug.jpg    | AT plug
File:BTC 5140 -- rear label.jpg | Rear label
File:BTC 5140 ISO -- top.jpg.jpg| ISO model top
File:BTC 5140 ISO -- rear.png   | ISO model rear
File:BTC 5140 ISO -- PCB contact side.jpg | ISO model PCB contact side
File:20210319 153518.jpg        |ISO model PCB component side
File:BTC 5140 ISO rubber domes..jpg|ISO model rubber domes
</gallery><br />

===5149===
ISO layout; PCB and controller chip are marked "5139", which indicates that the 5139/5149/5169 are sharing the same PCB, further proven by most if not all 5139 PCBs have contact pads to accommodate different layouts. This version has been found to suffer from [[ghosting]]; normally, potential ghosts are blocked, but playing Tyrian Destruct with two-player keyboard sharing revealed a flaw where a ghost could be emitted, requiring player 2 to use the alternative set of keys.

<gallery widths="250" heights="187">
File:Packard Bell 5149 -- front.jpg
File:Packard Bell 5149 -- rear.jpg|Rear view
File:Packard Bell 5149 -- rear label.jpg|Rear label
File:Packard Bell 5149 -- upper shell with sliders and loose domes.jpg|Loose domes over the sliders
File:Packard Bell 5149 -- PCB with dome sheets.jpg|Dome sheets over the PCB
File:Packard Bell 5149 -- loose domes.jpg|Loose domes; the single yellow dome is from the space bar
File:Packard Bell 5149 -- domes.jpg|All 102 domes
File:Packard Bell 5149 -- sliders.jpg|[[Keycap mount#Cherry MX mount|Cherry MX mount]] sliders
File:Packard Bell 5149 -- PCB, rear.jpg|PCB, rear
File:Packard Bell 5149 -- controller.jpg|[[Keyboard controller]] from Zilog
File:Packard Bell 5149 -- cable connector and earthing wire.jpg|Cable connector and earthing wire
File:Packard Bell 5149 -- cable label.jpg|Warning label on PS/2 cable
</gallery><br />

===5149 E5XKBM10140===
ISO layout, really hard but thin Abs keycaps. The backspace, and the large keys on the numpad uses guide shaft type stabilizers. The enter and the space uses wire stabilizers.<gallery widths="250" heights="187">
File:BTC51 5149 E5XKBM10140.jpg
File:Btc 5149 E5XKBM10140 rear view.jpg|rear view
File:Btc 5149 E5XKBM10140 labels.jpg|rear labels
File:Btc 5149 E5XKBM10140.jpg|without keycaps
File:Btc 5149 E5XKBM10140 keycaps.jpg|keycaps removed. some keycaps use wire stabiliser and some uses guide shaft type.
</gallery>

===5169===
This is a rare version of which little is known. It has been found with Wyse branding and colours in ANSI layout, with Wyse part number 770180-01 (where -01 is reported to indicate US layout).<ref>geekhack — [https://geekhack.org/index.php?topic=73732.0 Can anyone tell me if this board is mechanical and/or what kind of switches?]</ref><ref>https://www.worthpoint.com/worthopedia/vintage-brand-wyse-technology-1817900963</ref> The FCC ID of this version is E5XKBM111.