Philips HPL-N

Standard High Pressure Mercury Lamp with 50W, 80W, 125W (E27 base) and 125W, 250W, 400W, 700W, 1000W (E40 base) Features Yttrium Vanadate internal coated bulb Internal high pressure mercury discharge tube made out of quartz E27 base or E40 base (requires matching ballast) Soft glass (50 and 80W) or Hard glass (125, 250, 400, 700 and 1000W) Color rendering index Ra of 49 to 36 (lowest on highest wattage lamps) Typical lifetime of 16.000 to 12.000 hours (lowest on highest wattage lamps) Luminous efficacy of 36 to 59 (highest on highest wattage lamps) Cool white colour designation (4200 to 3900K colour temperature) Universal operating position Lamp control gear Requires external reactive inductive ballast (230V standard on Europe): BHL 50, 80, 125, 250, 400, 700, 1000W May require power factor correction capacitor for balancing line load

Best retro purpose

Mercury vapour lamps were traditionally used on industrial and street lighting and they can be used on these areas although LED lamps offer much better performance with lower energy consumption. There are still some specific uses that are specific to this technology. Light appearance is cool white with a bias towards reds as well as blues, and, especially ultraviolet.

Although this is rarely specified or even mentioned in datasheets, UV-A emission is significant if the lamp is used as is, with no cover. This means that most surfaces that are painted white look even whiter in this light. Trees foliage is also emphasized, so this type of lamps are very well suited in gardens. Flowers are not as well showcased as some colours are missing except for red, orange, white, blue and violet.

Houses can be properly light but such a lamp is less suited for living rooms, bedrooms but is well suited for workshops, halls or any other space that requires wide area lighting. Generally, low power lamps such as 50W are to be avoided as they are quite fragile so typical applications focus on 125 and 250 watt lamps and 400, 700, 1000W lamps are typically too large or cumbersome to be used as free standing lamps or in light fixtures. Due to the fact that fixtures are getting harder to find, outside applications such as area lighting should consider a minimal protection for lamps, meaning that floodlighting is harder than in the past. Of course, any metal-hallide and high pressure sodium fixture can be adapted, if found.

Durability and Repair-ability

Generally, mercury vapour lamps were very durable but more modern products were released with lower typical lifetimes. This is mainly due to the fact that upto the 70s, even into the early 80s, manufacturers focused on better performing lamps but this was detrimental to sales. Many installations were left as is with extremely old lamps that were still working, despite very low light output with a greenish tint, since they were not turned off and repairing them cost more than leaving them as is. Also, keep in mind that electricity was very cheap at that time. Many lamps could still operate with broken outer bulbs and left to be blown by wind, cope with mist and frost, although they were dangerous due to UV-C output.

Compared with modern LED lamps, mercury vapour lamps fare very poorly, as they have noticeable light output and quality degradation over 10.000 hours. However, they do have advantages. Hot or cold air affects them very little and they can survive direct operation in free-standing position, meaning with the lamp suspended on wires, even for their entire operational life. Ballast can survive tens of years if properly protected against direct rain or snow exposure. A very simple circuit means that lamp servicing is straightforward and risks are similar to mains voltage operation. 125 and 250 watt lamps are very well built and they were highly popular.

Greatest features & flaws

Features	Flaws
Good Windows 98/95 3.1 2D Gaming platform	No 3D hardware acceleration
Good MS-DOS SoundBlaster compatibility	Speakers can be easily covered with dirt or damaged
Good Video chipset and RAM expansion capabilities	Fragile, laptop upper case and display bezels, prone to many cracks
Good cooling, low CPU heat dissipation	Mediocre keyboard, trackpad, screen

Review

A midrange, quite slim, business laptop, released in 1998. It had an average mix of parts. Perhaps the single biggest issue is that the whole Dell CP and CPi range is very complex and difficult to understand. Differences between CP and CPi models is minimal in terms of aesthetics while most configuration options are difficult to spot. The major performance jumps are shown in the CPi lineup that has a Pentium II CPU model with major performance improvements, although the Pentium I option is still decent. The graphics chipset is quite fast, actually the best among Pentium I laptops, with good Windows acceleration and compatibility. Another rare feature is the presence of USB ports on a Pentium I era laptop, which is very nice and useful.

However, the typical mix of features of these laptop models mean that it also was obsolete by late 1998, just as most of the mid and high end IBM laptops, due to a lack of 3D acceleration. Windows 98 SE is a typical choice, especially if you have at least 32MB of RAM available. The Neomagic graphics is the top performer on 2D graphics both for compatibility as far back as Windows 3.1 and DOS as well as competitive with Chips&Technology or S3 Trio 64 videocards.

The LCD TFT screen is somewhat alright but far from being the best in terms of contrast and colour reproduction. However, the screen's brightness can be quite pleasantly set using keyboard shortcuts, as the laptop has somewhat more levels to choose from. As usual, DSTN or passive matrix screens should be definitely avoided due to their poor contrast, response, colour reproduction and brightness levels, no matter how lightly they were used.

The keyboard is not as pleasant to use as some IBM models, feeling somewhat light on keypresses. The palmrest is comfortable although the trackpad is somewhat bad in terms of sensitivity and response, being quite dependent on ambient humidity, as is also mentioned in the operating manual. The choice of a trackpoint system would have been much better. Also, due to the laptop's design, the lower area near the mid part of the laptop's case, between bays, is a common failure point due to the simple screw mounting point with no additional stiffening brackets.

The removable drive tray is a nice feature, offering both CD-ROM and Floppy drive support, which was a staple of period DELL laptops . The rechargeable battery has an unique self test feature that also shows the charging level by a simple button press. The BIOS and suspend battery uses a set of non-standard NiMh cells that can be quite messy if worn enough.

The lid closing latch is quite badly designed as it compounds the issue with cracks midway on the palmrest and cases's edge. The display's case is quite flimsy although the frame itself is reasonably well engineered. The integrated speakers are somewhat poor despite their positioning and size, being quite prone to failures due to water ingress.

The standard HDDs are quite competent in terms of size and performance, being well accustomed to the rest of the laptop's configuration.

Software support is great for reasonably modern (for its time) operating systems. Due to the video chipset, Windows 98 is the best operating system choice. Good DOS sound support is present due to the CrystalWare audio chipset that is Sound Blaster compatible, offering good MIDI and software support in MS-DOS.