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BSR or Birmingham Sound Reproducers may not be immediately recognizable to many readers and it wasn’t to myself. Based out of the UK, BSR was a fairly major producer of turntables that started up in the 1950’s and lasted until 1998 when they were acquired by Emerson. Like many companies in the 1980’s and 90’s they dabbled in the home computer market. The PC we’re going to look at in today’s article is branded by BSR and is one of the subtly oddest PC’s I’ve yet to come across. It doesn’t do anything “wrong” but some of the design choices are just unexpected and unconventional.

bsr1

The BSR 386SX/16 uses a fairly slim and light desktop case. To the left we have a rectangle power button next to three LED’s for power, turbo and HDD activity with a red reset button near the bottom. The turbo function is not initiated by a button but by keyboard command of CTR + or CTR -. To the right of the reset button we have a front PS/2 port for a keyboard. Having a keyboard port of the front wasn’t super uncommon on older 80’s PC’s but by the early 90’s  It was a much less common design choice. It is nice though to have a PS/2 port rather then the big AT keyboard port on a 386.

External expansion for the 386/16 though is rather weak with only two 5 1/4 external bays to the far right limiting your options for drives. I opted for a traditional 1.2mb and 1.44mb floppy combo which would of been typical for the time time but there is no reason one cannot ditch a floppy drive and add a CD-ROM drive or even find a combo drive.

bsr2

Here is a full view of the rear of the PC with the power supply on the left. below is a closer image of the interesting stuff on the right.

bsr3

Although it looks like there are more you really only have four ports for expansion as the two bottom slots are connected to the motherboard as well as the video port on the left. Other then the video lets take a look at the built in ports starting from the left below the VGA port and moving right.

The first port labeled “mouse” is the first of what I would say is a somewhat unusual feature which in this case is a built in bus mouse port. Bus mice along with serial mice were the two common interfaces for mice before the ps/2 interface came along and became standard. The BSR 386sx/16 uses a standard Microsoft InPort interface for the bus mouse. In my experience built in bus mouse ports aren’t terribly common but they also don’t really function any differently then a serial mouse would.

Here is an example of a bus mouse that I use on this machine.

bsrmouse

The connector for bus mice at a glance looks very similar to a later PS/2 mouse and can easily be mistaken for one but the pins are arranged very differently.

bsrmice

After the bus mouse port we have a printer port followed by two serial ports.

The case is easy to open. After unscrewing two screws on each side just slide the top and front bezel forward.

bsr4

bsr5

1) CPU – The CPU in the BSR 386SX/16 is unsurprisingly the Intel 386SX chip running at 16mhz. The 16mhz 386SX is one of the earliest 80386 processors and the SX designated it as a sort of low cost cut down version of the 386 with only a 16-bit data bus as opposed to a 32-bit data bus of a true 386 or a 386DX chip as they were labeled.  What this results in is a snail of a CPU which in many circumstances is slower then even a 286 running at the same clock rate and almost certainly slower then a 20mhz or 25mhz 286 that are only running at slightly higher clock rates. The saving grace of the 386SX chip though is its ability to run programs or games that require 386 code to run even if the chip is slower then its 286 equivalent. Unfortunately in the case of the BSR 386SX/16 the CPU is soldered onto the motherboard leaving few options for upgrade paths.

For a rough comparison I tested the CPU of the BSR and my 20mhz Harris 286 machine in Checkit 3.0 CPU benchmark

386SX-16  = 3234

286-20      = 3683

bsr6

2) Co-Processor – Next to the CPU we have an empty socket. This socket is meant to allow the later addition of a 387 math co-processor to assist in mathematical calculations. As I’ve said countless times before this was mostly useful for things like CAD programs at the time though a few games can take advantage of the co-pro. I upgraded my PC here with a Intel 387sx running at 25mhz which works fine with a slower CPU.

bsr7

3) RAM – The RAM setup on this machine is a little odd. Soldered directly onto the motherboard is 2MB of RAM. Connecting to the motherboard directly above the soldered on memory is a kind of little RAM daughterboard with six slots for 30 pin RAM. now as I cant find any documentation on the maximum amount of RAM the BSR 386SX/16 can take I cant say but on first guess I would say 16MB max but after finding a manual for a similar machine I now suspect the total max RAM is 8MB. Unfortunately despite my efforts I can not get the machine to recognize more then 4MB total. The two on-board and then two additional via the RAM slots. If I attempt to populate the other slots or use higher density RAM, 4MB for instance, the machine either only “sees” 4MB total or just plane refuses to POST. It could simply be an issue with my particular PC or my RAM as I find a 4MB limit unlikely for a 386 with that many RAM slots available.

bsr9

bsr8

*UPDATE*

After some more experimenting and finding a manual for a similar model I now believe the total RAM this PC can accept is 8MB. Focusing on this I did find a combination that gave me a total RAM of 8MB. This did not require messing with any jumpers or DIP switches.

ramnew

4) Switch – Here is the mysterious switch. most likely this is used in place of jumpers to set things such as disabling on-board floppy controllers and other functions. Unfortunately I can find no documentation on this motherboard so I’m left with no idea what these switches do. Also next to the switch is the Pizo speaker.

bsrswitch

5) Riser board – The riser board on the BSR 386sx/16 features four 16 bit ISA slots. Three are on the left side and one is located on the upper opposite side. The lack of more then one slot on the opposite side has to do with the video card which I’ll get to shortly. There is also a molex power connector on the riser board though I’m not entirely sure what purpose it serves. I would assume this is to supply extra power to the slots but I cant think of an example ISA card that would require the extra power.

bsr10

6) Power connector – Despite the PSU connector being a standard AT connector it is arranged in a rather non-standard way. Rather then having both of the connectors lined up next to each other as in just about every AT connector I’ve ever seen the BSR places them above and below each other. It achieves the same thing but its just a little odd.

bsr11

7) Floppy connector – On-board standard floppy controller supporting 1.2mb and 1.44mb HD disk drives. Another oddity is that the power to the floppy can come straight off the motherboard via a connector by the PSU connector and external batt. connector.

8) External battery connector – There is no actual CMOS battery on this motherboard, either RTC or nic-cad barrel battery only a connector for an external battery. Note that I have seen one other BSR 386SX/16 online that seemed to have a different revision of this motherboard that did have a RTC battery on the side close to the switch box.

bsr12

Video – The video on the BSR 36SX/16 is very interesting. AT first glance from the outside it appears to be a discrete card or maybe built in but like the RAM module the video is connected in a sort of daughterboard fashion.

bsr16

bsr18

Even more interesting is the somewhat rare video chipset this PC uses. The fabled Cirrus Logic “Eagle II” chipset.

bsr17

This video chipsets claim to fame is that it’s supposedly the only VGA capable video chipset that is actually 100% CGA backwards compatible. Many VGA video cards claim to be 100% CGA register compatible but in all known instances they aren’t actually 100%. The discrete video card version of this video chipset tends to go for high dollar amounts and is not very common. My own tests with the video card using the CGA tester program have turned out some incompatibilities but that may be due to the fact this version only has a VGA connector where as the discrete video card versions also has a hd-9 pin  connector that when attached to a CGA monitor may very well be 100% compatible.

The hard drive controller card that came with my system is from WDC. Its works fine with the Seagate 107MB HDD that also came with the PC. I have no idea though if the hard drive and controller card are stock but if I had to guess I would say yes.

bsr14

To round the system out I did add a Sound Blaster Pro 2.0 which I think is about the perfect card for a 386 system of any speed.

There’s not much else I can say about the BSR 386SX/16 except its a very odd system. It doesn’t really do anything innovative or revolutionary but what it does do it just implements in different and odd ways, not better or necessarily worse….just different.

bsr19

The CPU is an absolute snail as I said earlier and is soldered directly on but I suppose it does make a good machine for many early titles since it’s so slow but still has the ability to run games that need a 386. The video is also pretty uncommon and offers great compatibility for early games. All and all the BSR 386SX/16 kind of fits a nice little gaming niche between an 8088 and a 486 since your getting roughly  12-16mhz 286 performance but the ability to to run games that require 386 code.

Benchmarks

Checkit 3.0 – CPU 3234, NPU – 917.6

Topbench – 27

Wolf3d – 7.7

3dBench 1.0 – 4.4

PCP Bench – 1.1

Speedsys – 1.88

 

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2 Comments

  1. IMHO PSU connectors on mb are AT type, not ATX…

    • you are 100% correct. that’s what I meant to say. I corrected it and thanks for pointing this out.


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